I tested the five you posted. Overall, they're extremely good. Very impressive.
Notes:
I think we could probably replace one farenheit in the mono w/something else.
I'm of the opinion Discord is the most OP card in a war with these rules specifically. I'm looking for places to fit it in, but it's tough w/o overhauling some of the decks.
Remember I have a red nymph if we wanna use her somewhere.
The fire/light deck out deck is interesting. I tried fire/death and couldn't get it right as I'd said. I thought about fire/life w/healing or fire/earth w/earthquakes and stone skin.
Also, I don't think I've even met Kami. Is he around?
Thinking more about a 7th deck, if we wanted to make one: Based on what cards we have remaining, we could almost double the first graboid deck. We'd have to do -1 explosion, -1 rage to not break the 12 card rule (and then +2 of reverse time/lightning/blessing/freeze/fire eater/something else).
Edit: the +2 has to be fire, so maybe a pillar and a firestorm? I offered this as a possible solution only if you'd rather try something more speed rainbow than traditional duo-deck. If duo-deck sounds like an ok option it may be worth testing an altered version of the gravity/fire I posted, which was better than most of the junk I've used to clot this thread.