I think if your Chem teacher writes an excellent recommendation, that would go far to counter the B- (as well as a 5 on the exam).
It seems like much will depend on how you spin your activities and what your learned about yourself through these experiences and how they inform you on your goals and interests - and of course, how said university fits in. Once you’ve met the objective metrics (what is your SAT/ACT score?) ,you need to present a candidate whom, as others have pointed out in CC, the AO find likable and a positive addition to their community. Think about the general student profile for each school - do they value character / entrepreneurship / original thinking / whatever. You have more than enough material to craft nice applications for these schools.
What stood out to me were the volunteer experience in coding to tweens; tutoring gig; and, research on robotics/AI. (number of internships and locations? not so much, albeit impressive, because I would be more interested in what you did and learned - hence my interest in the robotics/AI)