I think the minigame's called the Grandslam, but I don't see how that realtes....
I guess I don't have a specific reason as to why I don't think the fire could've been caused by elements, but it just doesn't seem right.
And, also, Lynx and Harle were standing inside the orphanage during the fire, it's seems, to me, that, if they caused it, they would've taken Lucca, gotten out, then burnt it down, or however they would've done it, but that they wouldn't burn it down while they were in it.
The only double/triple tech that I know that is fire-elemental from non-fire-elements is X-Slash, or w/e the Glenn/Serge one is called, and that really doesn't start any fire or anything; although it is fire-elemental, I don't think it can start a fire because it really has no 'fire' in it.. the best example I can think of is being able to burn (rope burn, dry ice, etc.) someone without starting a fire