I'd really like to include a unique enemy in my portion of the map which is just a souped-up miniboss Imp, similar to the Uber Imp from the first ZDCMP. The rules state that I can't add any new monsters, though.

Would there be any objections from the crew if I went ahead with this anyway?

Depends on the way you are adding it. If it is well done and feels right, I'd say go for it. You have a good hand for things like that anyway, though I am not sure if it really has to be the... "Uber Imp" ...

For now I'd like to focus more on getting my areas done, so I'll just take the Uber Imp DECORATE from the first ZDCMP, if that's alright. I can always improve it at a later stage.

Sure thing - It's not your only slot

Just tried the Uber Imp as it is now and it definitely needs to go It's terrible and totally lame, sorry

If you're looking for a miniboss enemy, I don't think the Angel of Death has been used in-map yet. Might be worth a use there.

I spoke to Jimmy about it, and I think that the Uber Imp might be a neat easter egg to include in a secret area somwehere, as a reference to the old (though some tweaked sprites couldn't hurt). Definitely not there, though -- I've swapped that battle with a pair of Cybruisers for now (too early for the AoD, upon second thought) and gave the plasma gun in that area as a dispatch tool and a sort of 'reward' for discovering that somewhat out-of-the-way, optional path.

That's a nice solution, and having it as an easter egg might be okay