Start a new thread. Too confusing figuring out which are your questions and which are the OP’s.
My kids HS would not have allowed a sport to interfere with an AP science senior year for a kid who thinks he/she wants engineering. That would not happen. Unless the kid is a potential Olympic gymnast, I cannot see the logic here.
But it’s not my kid. Start your own thread and you’ll get some ideas on how to handle the tricky situation here. But if the kid was able to do DE for a programming course, why not DE for advanced chem or physics? That seems a little more rigorous than just “review and supplemental study” for a course taken as a HS freshman, no???