Search:

Yes. They both end with [ə] sound.

OK :)

When stressed:
О is always [О],
А is always [А].

When unstressed, those two phonems become undistinguishable due to the process of reduction (a phonem is a base phonetic unit of a...

Yes, you got it pretty right! (I mean stressed and unstressed О, А).

All your questions can be answered, the problem is you asked a lot of questions at once. It is not that easy to answer them...