I agree on all your points. I agree with Jon's decision regarding the Karstarks & Umbers, they need all the allies they can get against the undead, and those kids he had pledge fealty, as far as we know, are truly innocent. Taking away their homes, especially in winter, would be morally bad, and would lose allies from those who serve those houses.

But I still think Jon should be less of an ass towards his sister regarding her council. Sure, he doesn't want her to undermine him in front of others. In the society they live in that makes sense since the Northerners look to Jon as King in the North and probably don't respect Sansa themselves. But even when she councils him in private he still rudely shuts her down, rather than saying something along the lines of "I hear your council and understand it, but the army of the undead is the biggest threat to the living".

As a show watcher though, I do feel Sansa is more right than wrong. I do expect Cersei to follow through with her intentions of marching against the Starks despite the winter. And an army marching against you from the rear, even if it's a southerner army unsuited for war in winter, will be a huge hindrance when trying to stop the White Walkers. And Cersei is someone who would not join the fight against the White Walkers unless she has undeniable proof of their existence, if she is able to put aside her hatred for the Starks. She's clearly overconfident though so I don't see that happening