I wouldn't take too much notice of post #4, you don't need it on paper to show your good at maths and physics but a qualification in the subject will do you no harm.
He is right saying that GCSE's and A-levels wont count for much after you gain a self sponsored 0-fATPL or an Ab-Inito.
But keep your options open for sponshorships like this:
http://www.cabair.com/sponsorship/index.htm
Have an absolute minimum of two A levels, to include Mathematics and Physics (or science based subjects).
I think the choices you've put up are good, Maths & Physics will make your ATPL's easier to digest and possibly get you on a sponshorship. The other 2 A-levels will aid your chances on getting to the flight deck as well as support a backup career. 