Thanks for the reply and addressing to the questions I've asked!
I'm glad you're not rushing with the game release, as working under pressure never ends well (ekhm - Cyberpunk). Your game has a lot of potential and I believe the final product will be awesome!
To be completely honest local coop, for me, is the thing this game needs. I am not intending to somehow force you to consider this mode, but local coop was the first thing I thought of when I saw your game, especially when there was another character in the duel mode :P
Anyways, I am wishing you luck with finishing the game!