Oumayma
Yes. Oumayma is formed from classical Arabic diminutive morphology applied to 'Umm' and appears in traditional Arabic naming practice; it is attested in Maghrebi and other Arabic-speaking contexts.
No. Oumayma is a lexical diminutive of 'Umm' and is not a Quranic proper noun.
The diminutive form appears in early Islamic onomastic records and family registers; it has been preserved in regional usage, especially in North Africa and in transliterations used by Malay speakers.
It conveys affection, nurture and familial warmth through the diminutive of 'mother' rather than indicating literal motherhood.
Common transliterations include Umayma, Umaymah, Oumaima; the initial 'O' form reflects Maghrebi/French orthographic influence.