Our HS requires students take honors bio, chem, and phyics before enrolling in the AP level class. But every HS is different so I recommend she work with her teachers and guidance counselor.
I would shy away from two lab sciences in a year unless one is a real science whiz kid.
Keep in mind that junior year can be hectic with studying for standardized tests and, in many cases, taking on leadership roles in ECs, starting to visit colleges, etc. It is great to take a rigorous schedule but don’t overload.