Two things; firstly, will you control the monster chosen or shall I? Secondly, I'll be using the @(whoever) option more given the activity that is starting to spring up and so things aren't confusing.
To simplify conversations, you could add a rule that requires people to mention a user when interacting so it's easier to know who is in the area/interacting with who.
A monkey owl sounds really cool! I don't see wolf elephant though you may need to explain that to me Also trying to wrap my head around a giraffe racoon