BCCC to ABB? What should I retake? any general advice?

You can definitely go from a B to an A and from a C to a B without retaking anything as long as you put the effort into it. I got a B in Biology but I'm hoping to get an A overall without retaking it. (I'm 6 UMS off an A at AS)

If you're up to it retaking a subject wouldn't be a bad option, again as long as you are motivated and up for it. I actually would've said retake Psychology as there isn't as much to learn, but you're dropping that.

A lot of people ask if it's possible to go up two grades from AS to A2, and it is, although it would take a lot of hard work. But to go up a single grade is extremely possible, so don't be disheartened.

I'm rambling but if you put the work in you can go from B>A, C>B, C>B. Retaking and getting a better grade would obviously make it easier but it would be a lot more hard work. As for the EPQ, personally I'm doing it next year but I wouldn't have took it on if I was resitting anything. A lot of work and deadlines are involved. This is completely my opinion but the amount of time spent working on an EPQ could be better used in raising your grades next year. Good luck with whatever you decide, everything is possible as long as you work hard for it.