You're right that Japanese isn't really stressed, but unfortunately, I'm very thoroughly American--I can't help putting stresses in words. ;)
As far as I know, ah-yah-kah would be correct for
Ayaka, and eye-ay-kah would be correct for Ayeka / Aeka. For any more information than that, you're far better off going to the Facts board--I'm actually a student of French, lol. I just had an Anime Phase some years ago and remember a bit of what I learned from it. :D
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