The really nice thing about mixed breeds is that their negative behaviours of their lineage is often minimized.
No; like all living individuals, it’s a crap shoot.
The best way to avoid problems is to start out right - looking at how the dog behaves as is and being serious about it rather than feeling sorry, or thinking it’s cute.
It’s wonderful to live in a country where we can choose to get a mixed breed from a shelter or a purebred from a breeder. For now.