so my only real childhood experience of the teenage mutant ninja turtles was (several repeatedly rewatched VHS episodes of) the 1980s animated series

So I probably didn’t get all the lore, but

The mutagen was supposed to change individuals based on proximity to other species – the turtles became humanoid when exposed to it because the creature that had most recently been in contact with them was the human guy Hamato Yoshi

who apparently then went and hung out with rats for a while before his own exposure to the mutagen, resulting in him becoming Splinter

Which makes me wonder, is there like, a difference between mutants who started out human and mutants who started out something else

And which kind were Bebop and Rocksteady

Because (I rewatched the episode to be sure) all we ever see is a rhino and a warthog getting captured, and a couple of human guys getting captured… and then later we see the mutant henchmen that resulted from this?

so, were they a rhino and warthog that turned humanoid because of being exposed to mutagen near the humans

Or were they humans who became rhino-warthog-oid from being exposed to mutagen near a rhino and warthog

And whichever they were, did the others exist too? and what did Shredder do with them

Were the two sets of mutant henchmen identical and just get swapped out from time to time and no one noticed

(going by the chaos that was 1980s cartoon series plots, there are probably at least some plot points that make more sense if you assume this)

Don’t even know lol