First, the object of video in your examples would have to be accusative, not nominative: nonnullas/quasdam/aliquas feminas video.
Each of these words agrees in gender, number and case with the noun it modifies, and the case of the noun it modifies is determined by the noun’s function in the sentence, not necessarily the genitive.
Aliquot is indeclinable, but the case of the noun it modifies is also determined by the noun’s function in the sentence. Aliquot feminas video.
My apologies. Feeling just a little dumb there to be honest. Yes, understood, obviously, accusative with a transitive verb. So let’s change the verb to “adesse”. You answered confirming the accusative but there are many examples in texts using the genitive :
It looks like in your example from Google books, de laudibus aliquot feminarum gentilium…, the context of the sentence is requiring the genitive. We are talking “about the renown of some pagan women.” It is genitive because it’s qualifying laudibus.
Aliquot is indeclinable, and therefore perhaps conceals the structure of this phrase to some degree. Feminarum is genitive not because it follows aliquot but because it depends on laudibus. Aliquot modifies feminarum. If quidam had been used, it would be de laudibus quarundam feminarum gentilicum.