I doubt they are hybrids - it's possible to hybridize corys, but I have yet to see any posts about ones that are hybrids for sale. There are two hybrids listed in the Cat-eLog, but neither look anything like yours. Since most corys are relatively easy to breed naturally, there is less incentive to try to mix up the species like they do with Synos - the main reason Synos are getting hybridized is the difficulty in breeding some of the species.
I'm not very good with corys - there are too many that I haven't seen in real life and there are many very similar species.
Fish A's photo isn't very good, because we can't see the pattern in the dorsal fin - If it's got a blotch in it, it's likely to be
.
A possible candidate for your "Fish B" is
.
But those are just identifying by picture/Cat-eLog and Ian Fuller & H-G Evers book on identifying these fish, and with no personal knowledge of either of the species.
--
Mats