im sure more rigorous schools like TJ or Exeter will make you use a bit of MVC in e+m, because in college you will definitely have to use it. But at my school, which is actually one of the most rigorous math and science schools in the nation, no actual understanding of MVC is required. The most our instructor taught us is that a line integral is "like a curtain, but don't worry about it because you can basically just do it like a regular integral in all our problems." So I wouldn't worry about it. If you have a decent understanding of Calculus at the AP level (decent, not even excellent. Though I got a 5 on the calc before taking physics, i know i learned a lot of calc THROUGH taking physics) you should be able to tackle physics. I mean who knows, some people actually like thinking about physics mainly conceptually, and for this your mathematical intuition doesn't have to be that solid (for setting up equations and solving problems).
concerning physics B, if you're considering engineering, the B is pretty useless. physics B is more of a broad, shallow physics curriculum, certainly not what you want if you need to apply it to engineering. Moreover, if you're only concerned with credit hours, some schools may not even accept B for engineering, will only accept it for certain tracks, or may not award you credit for both b and c. Make sure you look into this. APs are expensive
and this could add useless classes to your senior year schedule