Of those 2200, we had about 400 seminary students. Now, that doesn't give you exact numbers, because not EVERY Mormon kid enrolled in Seminary, but most did. Also, this was the 80's. From the googling I have done this morning, I think the percentage of LDS people in Mesa as a whole has gone down, but no idea specifically for the MVHS area. Probably safe to guess it's roughly the same as when I was there, or slightly less LDS since the trend has been to move out of Mesa to the newer areas.

I don't know about Olympus Cove. I'd guess much more LDS than the MVHS area.