...No "good" Volcanic Deck in Duel Links would include Doomfire. It's far too costly without Blaze Accelerator Reload.
Volcanics are probably missing too many cards here to be viable. I guess you could TRY a Gem-Knight hybrid, but the Pyro Fusions aren't as good as the Rock or Thunder ones.
"I'd be down for that for the sole reason it would make Purgatrio finally gets hit, if the deck becomes meta."
No, even with Purgatrio, it won't become meta. Invoked engine only gives a winning option and improves consistency. We don't even need to play 3 copies of them, with the Dec 15th ban list is enough.