No cat people. As far as you know.
God, The felinids are a Whole lore rabbit hole.
While their is basically no lore on them from official sources, aside from "they exist", If you look at their RL origins you actually get more lore about them, at least what they look like. From what I have heard, The fist mention of the felinids was a Necromunda player Who mailed into white dwarfs asking if they could Add the Puma sisters from Dominion tank police to their game, Of which white dwarf said yes.
Other origins I have heard Are that a player won a tournament and could add on lore piece of his choice to the setting, and he added Cat people ala thundercats.
Are both of these mutually exclusive? No, Can both of these be talking about the same person? Maybe, Are their multiple Cat hybrids Labeled as felinids ranging everything From Dominions Tank polices Puma Sisters to Thudnercats categorized together because the imperium jus tlabels stuff like that as abhumans? Quite Possibly. Can you make All of this work In setting? Easily.
Early 40k was silly as shit, their is a canonical Inquisitor named Obiwan Sherlock clussue, Who is from the first rouge trader, Being the FIRST NAMED INQUISITOR EVER.
When I tell people to not to worry super hard about what's 40k Canon and Just pick some pieces and discard others that fit best with the story your trying to tell, this is what I mean.