Please God don’t make Han glow…
Ambiguity is fine, but I don’t want a confirmation that he’s “real” in a Force ghost sense. To me, that scene is entirely metaphor for what’s going on in Ben’s head and it was surprisingly effective at that. To me, Kylo didn’t actually have a vision of Han and didn’t actually speak to him - sure, that’s out of character for the series, but it worked very well for me.
Then again, I’m the guy who still maintains that Rey killed Leia by mistake and no one agrees with me, so…