question

If G2 and m80 both qualify for champs but m80 finish higher would G2 be kicked out of VCT? because it's their second season and they would've finish lower than the other ascendant team

yes they will be kicked out and go straight to ascension instead of going through all the challengers

Basically yes. I believe the lower placing team will be relegated in this case G2.

The higher placing team gets a guaranteed stay for another year while the lower placing team has to win Ascension to stay