Yeah, that's possible.

Right now, modders are still sorting through a new error that started appearing after the latest game hotpatch. But, yeah, it's possible.

You can specify color, livery, and pattern for each new AI car if you want.

A couple examples that use new colors and combinations of liveries and patterns:

AI set for RammerRS
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1930089784

Wingman and Outlaw AI sets and skin pack(Hotshots,Bulldogs too)
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1989445672

Ok that gives me hope for the next question,

Let say AI 1 Has a name "Jeff" and AI 2 "Tony".
Is it posssible that for every race Jeff (AI 1) will use always speeddemon with Black color and Tony will always use speeddemon but always white?
This question is really important to me for making a new bot tournament and if every bot will have his "assigned color or skin" it will make perfect show :)

Yes(sort of), if you make a new .cavs file for each AI car. Instead of being called "Speed Demon", the car2 could always be called "Tony".

There would still be some random AI name at the side, though. Those side driver names can also be customized but I haven't found a way to control which car gets which side custom name.

Creating custom .cav files for each car is a bit more work, but it should do what you want. Plus, if you make custom .cavs files, you can also specify any upgrades exactly. For example, I tend to make my AI cars B class maxed out at 234 points.

If you make custom .cavs, you'd be limited to 23 AI cars, though.

Right now, AI selection in Wreckfest isn't fully random. For example, if I start a Custom race with only one AI car, that car is always a Hotshot. The skin may change from race to race but it is always the same car.

Bugbear said they were working on a fix for that but that was several updates ago.

Thank you kindly for explain :)
I'm newbie but i'll try to find tutorial about editing or creating cav. file.

But about first car for AI (hotshot), this also happen on multiplayer server when you are trying to add bot?

I'm not sure.

Oh, and that Hotshot is if I start a B class race.

I think things are different for online matches.

I've never tried making a custom AI list for online.