Basically a free play mod inside of multiplayer so it would be normal free play, but with ur friends, i feel like it would be awesome for ukebash and possibly future mods

I feel like this is just classic.tbm with rtg and reactiontime set high

If this is what you suggest, it won't happen.
If you're looking for the same mod as in Free Play, it's called classic.tbm and is playable in multiplayer, just as Froog has said.