...if Ned's words about lone wolves are to mean anything for the Starks themselves.
"Let me tell you something about wolves, child. When the snows fall and the white winds blow, the lone wolf dies, but the pack survives. Summer is the time for squabbles. In winter, we must protect one another, keep each other warm, share our strengths. So if you must hate, Arya, hate those who would truly do us harm. Septa Mordane is a good woman, and Sansa... Sansa is your sister. You may be as different as the sun and the moon, but the same blood flows through both your hearts. You need her, as she needs you... and I need both of you, gods help me."
A lot of discourse has been spun over that GRRM interview where he mentioned killing Sansa off as a future possibility. I'd posit that there's a pretty good reason to believe that Sansa needs to stay alive and not just be killed off or die in the Vale due to some slipper shenanigans or mouse kidnappings.
The reason is that without her, there's really little meaning to Ned's words. Just as she was in the first book, she still serves the role of being, to be honest, the only source of potential conflict within the Stark family especially in the context of any future reunions. Without genuine conflict between the Starks, what meaning is there really to be had with them being able to put aside their differences to protect each other? If Ned's words are to mean anything important, you need a real conflict for the members of the family to set aside.
There's only 5 Starks left: Jon, Bran, Rickon, Sansa, and Arya, and we can work our way through the different groupings to see that really there's not much tension without Sansa there.
Rickon is 5 years old. While Georgie plays a bit fast and loose with character maturities, a 5 year old being raised on Cannibal Unicorn Island and warging his childhood away is still probably too young to really have any meaningful disputes with his siblings. At worst he could be a rowdy pawn for some 3rd party holding him hostage, but I don't think that's the meaning of Ned's words. Not much in the way of inter-personal conflict potential with Rickon vsv the other Starks.
Bran could have some conflict but he's geographically isolated and is being trained to be a wizard with interests that extend far away from personal squabbles. Perhaps his wizardry leads to him having some opinions that conflict with the rest, but those reasons are likely supernatural and probably come with insight into important goings-ons in the past and far north that it still doesn't strike me as a strong source of personal, inter-family conflict. Also Bran is still quite young, alone, and disabled. Similar situation as Rickon in that not exactly sure what he could do other than be a pawn for someone else so a political squabble is unlikely.
So that leaves the three eldest with Jon, Arya, and Sansa. I don't think I really need to spell out why Jon and Arya are unlikely to have any significant disagreements with each other. Their closeness growing up and even in the present have already shown willingness to risk themselves to preserve/protect that connection (Jon forsaking his vows to rescue fArya from Ramsay, and Arya defying the Faceless Men and keeping Needle). Not likely to be much in the way of political disagreements between them either given the suspiciously Sansa-shaped elephant in the room with regards to any succession questions.
So the only real likely sources of inter-personal conflict within the family would have to come from Sansa-Jon or Sansa-Arya.
Sansa and Jon could easily have conflicts with each other. Not for any childhood grudge reasons, but just for the fact that of the Starks they were the least close. They really didn't share too many common interests growing up and Westeros is a highly gendered society anyway especially in child-rearing so they just didn't spend that much time together (was Jon ever going to hang out with Sansa and her Septa for needle lessons? Doubt it). That in and of itself could be a source of conflict because unlike the others they really don't know each other that well. They wouldn't immediately know what to expect of the other and if by the time the two are doing anything political, they'd also both have followers, courtiers, etc. who would have an interest in pushing their guy and wouldn't think twice about voicing concerns about this other Stark they don't know and don't support who might get in the way.
There's also the issue of Winterfell's Succession. If Jon were to be resurrected and come back different, less inhibited and bound by notions of Duty or Honor, it'd be very easy to see him making a push for Winterfell. He might also have someone like Melisandre whispering in his ear about how he's the Lord's Chosen and destined for greatness and yadda yadda. If Robb's will comes to light, that would only reinforce any feelings of entitlement and desire he would already have.
Sansa herself still desires Winterfell and has the best normal claim vsv Jon. Robb's will is a monkey wrench if it goes public, but it's also not binding in any actual real sense. Sansa could easily argue that the context the will was written under no longer applies. Robb disinherited her because she was a hostage of and force married to the Lannisters. That is no longer the case. In any situation where Sansa is doing anything political she'll be doing so in fact in direct defiance of and open rebellion against the Lannisters who have already declared her a kingslayer. 2+2=4 it's not a difficult hurdle especially for those that are already in Sansa's camp and wouldn't benefit from pushing a dodgy will that supports someone else.
What the will could do very easily, building off of how Sansa and Jon don't really know each other that well compared to their other siblings, is in creating a deeper emotional sense of conflict/betrayal. Regardless of the context around the will, it might still hurt that she was disinherited and it might lead Sansa to striving harder for Winterfell and even holding some poor opinions of Jon if/when he asserts his own claim to Winterfell. Jon would be a more enigmatic figure for her and she wouldn't be able to get a good read of his true motives (whatever they are. His motives might truly be malicious if he's going full wolf-blood by this point) and thus her perception of him could get colored by hearsay and rumor. This also doesn't even take into account how she might not even believe the person claiming to be Jon is in fact him. She could definitely hear stories about Jon coming back from the dead and making a push for Winterfell, but anyone can claim to be someone else especially if that someone's name could earn them power. Unless they meet, there's good reason she might not necessarily trust that it's actually him.
This goes both ways and Jon, similarly, wouldn't be able to intuitively know/feel Sansa's true motives or opinions of him. Most he'll have to work with is what other people say of her, and if he learns about the fArya situation with Jeyne, then this would be the 3rd time thinking someone is his sister. He might not trust that she is who she says she is unless they actually meet.
Easy to see how this dynamic of mutual distrust and the unknown spirals out of control.
This then leaves Sansa and Arya whose relationship Ned's entire speech was directly addressing. George has already said before that they "have a lot to work out" though that could mean a lot of things. Not only would the two have whatever childhood tensions might still be lingering (though at this point, after all that's happened it'd be odd if that were a major issue), but the two are still very different people from each other. Perhaps there's even some tensions that bubble up if Arya gets wind of Sansa's involvement in Ned's imprisonment and holds it against her. If Sansa is still under Littlefinger's thumb/influence, then I'm sure he'd be whispering in her ear and stoking conflict while unhappy with how his key to the north could have competition/could even see Sansa herself slip out of his groping grasp if he doesn't ensure the two distrust each other. Likewise if Lady Stoneheart is still around, I doubt she'd be a great influence on Arya with regards to forgiveness.
There could be a class component to their conflict.
If Arya connects back up with the Brotherhood, they're not exactly the Lord-Loving types to say the least and Arya in general has a higher affinity for the lower-classes. On the flip-side, if Sansa were to rise to power in her current circumstances and Rally the Lords of the Vale, well, it'd be the Lords and Knights of the Vale supporting her. As far as Lords go they haven't done much pillaging and at this point there really isn't anything left to pillage (especially in the Riverlands where the two would groups could likely interact), but it's not like any Lords of Westeros are great to the common-folk. Any leader is going to be limited by the sensibilities of those that follow them and that could lead to tension between these two Starks.
There's also the magical divide and religious divide between them. While Sansa doesn't disregard the Old Gods, she does show a higher personal affinity for the Faith of the Seven and any Vale lords who rally to her are going to be more Andal Faith oriented as well. Also Sansa is the least magic/wilds inclined of the Starks. In the battle of Man vs Nature (a common theme in the series) she is currently far more humanity aligned than Nature.
Compare that to Arya and the Brotherhood. Arya herself is very attuned to Nymeria, the wilds, and is more enmeshed in magical things. The Brotherhood are r'hllor oriented and have been led by two resurrected zombies.
A lot of opportunities for inter-family conflict that comes from their respective personal affinities but also the circumstances of the potential followers around them.
TLDR: If Ned's words about Starks banding together in times of trouble despite conflicts between them are to mean anything, then Sansa has to stay alive for that to happen as without her there's not much for the remaining Starks to have to put aside in the name of family.
