Per Silverleaf, I'm gonna go ahead and preemptively delete my posts here.
I'm making Variant heroes because of how much I love the Bloodsworn Coliseum Title Cards! End of topic!
Let me know if I can show my work, admin types. 
What kind of irreducible damage? Fluffy Bunny damage, right?
Not Fluffy! I fixed the thing I can't talk about presumably. Deleted content!
I can't comment on the appropriateness or otherwise of using card art, but I know that you're not allowed to post custom decks here or even discuss them. Whether that applies to promos or not, I don't know, just a heads up.
Thanks! I went ahead and purged things. I'll put them up if I'm told I can!
You are, however, welcome to make variants and post them elsewhere (eg on bgg)
Alternate character cards used to be okay. Don't know if that has changed.