As long you use Unreal Engine, you are a legal EpicGames partner.
They grant rights to use the Assets in your games; engine Eula grant rights to promote the “game” you see fit…
But, the characters still are their property and they can tell you to “drop” whatever you’re doing if they feel like so.
There was a hateful violent game released a while ago, EpicGames told them to remove Unreal Engine logos from their games, an example; they can do the same with any other assets you use from them.
Anyways, these characters have no value for a “real” production now.
In few months asset flippers gonna have them in “games” all over Steam store.