the sound between the d and the v from a minimal schwa "ə" in the direction of "ă" or even "ah" (as in "Avenue" or "Ave Maria")
and
In my dialect (and this is a fairly widespread but not universal feature in the US) the three words underlined in the sentence "So taken was he with the young lady's attitude that he decided he wanted to marry merry Mary, when spoken at a normal conversational clip, are pure homophones.

Novel, to my ears and thus not pedantry (to me, anyway) Haruo.

My Oz ears distinguish "Avenue" (where the 'ave' is pronounced as in "have") from Ave Maria, which is pronounced as you have indicated in your neck of the woods. Similarly, my Oz ears hear 'marry' as in "have", 'merry' as in "bell" and 'Mary' as in "airy" and thus not as phonemes in the sense you described.

Cheers, Rowan