Monster Hunter Wilds finally has a release date, will mark the first simultaneous PC launch in the series

Unfortunately no (unless thats a new unannounced feature in this installment) They help/follow you around during missions like a buddy/partner. That said, they have different armors and their own "character creator" so you can customize and dress up your own lil guy.

To add to Pfifel's comment, you can't play the cats in this game but you can in Monster Hunter Generations and Generations Ultimate. Generations is stuck on the 3DS, Generations Ultimate is on the Switch. GU is basicslly like a best-of Monster Hunter that incorporates all the previous games in one form or another, either by including all the previous villages or a lot of OG monsters, and playing as a felyne is sorta like an additional weapon.

You have them as your companions and they help you on hunts by fighting alongside your hunter, setting traps, and doing other miscellaneous support moves, but they are playable by yourself too. The gameplay is pretty much the same just from the cat's POV and a different moveset. Plus, the weapons aren't as varied. Still lots of fun.

Here's a video going over how they work in Generations: https://youtu.be/-JkNVpbfJKI?si=fhe3x9P19U6vpzrK

Might be a little confusing if you're completely new to the series but still worth a watch, imo, since gaijin hunter makes really good tutorials overall