Any talk of a red card for Kane is pure fantasy.
Yes, Kane looks for Lallana but all he does is places himself between Lallana and where the ball is going to land, effectively saying "either I get the ball or you foul me" which is in every way a legitimate part of the game. He doesn't back into Lallana once he's airborne, the coming together was all Lallana's doing - with Kane where he was, he had a choice of pull out of the challenge or give away a foul.
What Kane shouldn't have done was "make a back for" Lallana, but it's understandable given he knew he was about to take a whack and it doesn't change that the foul was by the Brighton player. He certainly didn't "tackle him in the air" for those making a spurious rugby comparison.
For the record, the Salah incident was also a penalty in my book. It's one of those where I wish the penalty could be given and also a yellow for simulation because Salah didn't half make a meal of it, but a foul none the less. Additional caveat - refs need to start giving pens for fouls like this if and when a player doesn't go to ground like he's been shot, because it's still a foul and maybe then players like Salah (or Kane, Lamela, Vardy, Aubameyang, Aguero, Martial etc etc) won't feel the need to go for a triple twist with pike and added yelling.