Bwahaha, yeeeesss. And nope! Nick has probably not seen the little babyface spawn yet.
Nick has definitely popped up a couple times over the years, so yes. Probably knows Kass by now. Extra kid sister vibe works, except Nick probably hit on her now and then. Because he's a jerk like that. BUT as for her and Jes, well. He's supportive in an unspoken way. He doesn't really vocalize his support for Jes and Owen's choices, but the non-asshole part of him is happy his twin sister has someone. Even if she has to rob the cradle to find 'em!
Likely saw a bit of Cal back then, yes, but largely ignored his existence. Cuz Pegs doesn't exactly talk about her relations and stuff. BUT, Nick is probably cool with how Cal turned out. All cocksure and Youtubey and shit.
Oh yes. Nick is prepared to hate on ALL the stodgy A-team types! He declares Milo a pinhead. :D