Does removing a Uplay game from your Steam account also remove it from Uplay?

I want to remove Assassin's Creed: Unity from my Steam account. Would this also remove it also from my Uplay account?

I do not think so. UPlay and Steam are two entirely different platforms and you can launch a gamefrom UPlay, without using Steam.

Additionally I do not see a reason why you would want to remove a game from steam, if you bought it on steam.

No, it won't remove the game from Uplay but whenever you launch the game from Uplay it tries to check Steam first to prevent this sort of thing, which is the reason why you can't run games with Uplay with solely one client, both of them have to be running. (which is one of the things I hate most about Uplay)