Granted that we lack evidence either way, on most aspects of the argument. Take the cloning of Queens: both the Thompson and Krige models have appeared, died, and appeared again. So either the Borg clone the bodies of satisfactory Species 129 individuals whenever they need a curvaceous Queen - or then this Species 129 features only a limited number of phenotypes that naturally repeat (like the Benzites seem to, as per "A Matter of Honor"). It may also be that the various Kriges do not actually look anything alike: only the heads, which are artificial through and through, are identical.
And yes, the Borg might have been their VOY selves all along, including before and during "Q Who?". They do have different mission profiles on different occasions; not every sortie would involve kidnapping Captain Picard and assimilating his crew.
Finally, any abnormal Borg encountered may be just that. VOY suggests the Borg are secretive; so if our heroes ever actually encounter some Borg, these may be damaged or otherwise aberrant individuals who do not quite represent the mainstream Collective and its wish for secrecy.