Looking through Jungraithmayr's (2013) La Langue Mubireview, I find 14 plurals of the form BaCaaDi(i)F (e.g. àbàlány "patas monkey", pl. àbàalîny) and 5 of the form BaCaaDo/u (e.g. móngò "monkey sp." > mánáagò). Of these, 9 and 4 respectively are found in Jullien de Pommerol's (1999) Dictionnaire arabe tchadien-français (including, to my surprise, both the previous examples), and many of the remainder seem semantically likely to be features of some more localized Arabic variety (e.g. mánjàk "village chief" pl. mànáajìk, various ethnonyms). It seems rather clear that these two plural types are borrowed from Arabic; but there is no strong evidence that they have been extended to inherited vocabulary.
For the closely related plural form BaCaaDiFe, we find 3 examples, of which only one is definitely of Arabic origin: shàddáarì "shaman" (i.e. "herbalist", based on Chadian Arabic šadar < šajar), pl. shàdáadìrè. Suffixation of -e is not otherwise typical of Mubi plurals, and matches perfectly with the Arabic plural in BaCāDiF-ah; it thus seems reasonable to consider this plural type as a borrowing from Arabic as well. If so, it provides us with one good candidate for an extension to inherited vocabulary. Mubi érìny "scorpion", pl. àráarínyè is comparable to other East Chadic forms in its singular, eg Dangaleat ɛ́rîndílɛ̀ pl. ɛ́ríndílnà, Toram irindeeɗà pl. irindeɗ, Kajakse ʔàràari pl. ʔàràaràk (Fedry 1971, Alio 2004), but disagrees strikingly with them in its plural.
At first sight, one is tempted to go further and conclude that the plural types BuCooDuF and BiCeeDiF are also adaptations of the Arabic iambic plural. But the evidence in those cases is not so clearcut. BiCeeDiF is only attested for a single word with no Arabic counterpart that I've been able to find (dólgúm "a type of basket", pl. díléegìm.) BuCooDuF is far more frequent than BaCaaDi(i)F and seems to contain a much greater proportion of inherited vocabulary, although some Chadian Arabic loans are found as well (e.g. àngúmbùl "calabash", pl. àngùnóobùl, corresponding to Chadian Arabic amgunbul pl. amganâbil). Moreover, it can plausibly be unified with another plural schema with no possible Arabic counterpart, BuCoDFuG, e.g. áránjálà "kidney", pl. ùrònjúl. For the time being, it seems prudent to withhold judgement on the explanation for why these two plural types are so strikingly reminiscent of the Arabic iambic plural.
Other Arabic plurals borrowed only for the corresponding Arabic nouns include BuCuuD (e.g. tês "billy-goat", pl. túyúùs), BiCiDaan (e.g. jédì "dorcas fawn", pl. jídíyáàn), and the sound masculine plural suffix -iin (e.g. máanì "strong", pl. màanìʔíìn). In the case of the sound feminine plural suffix -a(a)t, only two of the four examples in Jungraithmayr are clearly of Arabic origin (àntàháarà "mantis", pl. àntàhàarât; ràbàʔíyè "young woman", pl. ràbàʔìyáàt.) The other two look suggestively Arabic, however (ìrèedíyè "small granary", pl. ìrèedìyât; ròomìyè "crushing-stone", pl. ròomìyáàt), and this plural type too probably consists entirely of Arabic loans.
So far, it looks like in Mubi, as in Berber, Arabic influence has had the effect of further complicating an already very complex plural system. But Mubi is spoken in a far more multilingual context than most Berber varieties; one wonders whether some of the complexity here might be due to contact with regional languages other than Arabic as well...