Shlomo Morag, who studied Oriental Hebrew pronunciation, says:
"No community maintains, in the realizations of the vowels, the distinction between a 'long' and a 'short' vowel ('tenuʿah gedolah' and 'tenuʿah qeṭanah'), a distinction prevalent in later medieval grammatical theory. In most communities long realizations of the vowels occur in stressed syllables. The Yemenite community maintains the distinction between ultrashort and ordinary vowels, the mobile šewa and the ḥatefs being realized as ultrashort vowels."
Yet you say you know for sure that non-Yemenite Oriental Jews pronounce אָחִי as /ʔaːˈħiː/ and אֲחִי as /ʔaˈħiː/, which would create a minimal pair. You seem more knowledgeable about the Ashkenazi pronunciation than Morag, but at the same time you say that you don't know the full phonologies of the Oriental pronunciations and Morag's work is the only one I can find that does give a full phonology.
So do Oriental Jews have phonemic length distinctions or not?
(I apologize for copying this from my other post, but you didn't answer there. If this is improper, you can delete this post but do answer the question in my other one.)