After all the problems you've encountered and lessons you've learned , it seems like a quite simple decision here Candyman.
Give all your leftover discus , fish and plants to your nearest LFS in an exchange for food and other tank necesities , nuke the tank and filters with bleach , and start over fresh with a new batch of 15 or so discus .
I wouldn't risk it any other way IIWY . Especially not after all the disease problems you've been through .