Question about level-extending mods -

I am using both UnlockLevelCurve and also Expansion alongside Homebrew. What happens to the effects that is given to classes post level 12? Can I level up and get those subclass/class features from those mods, after the progression for BG3 homebrew ends?

Also another question - if I add a new class via a mod, it wouldn't necessarily not work, right? it'd just be balanced way differently. Am I correct on this?