I think if it isn't a Dual type, the Fire types will become Normal, like what Roost does if a Pokemon is pure Flying (which really can be only done by another move) because the ??? type or typeless don't exist anymore since Gen V.
As for the Talonflame nerf, while it was really broken in doubles, in singles it was pretty much you needed Stealth Rocks or lose, I'm so happy with the nerf as a single battler
As for the re-typing of Cyndaquil, I don't agree with it at all, re-typings should only be done when there is a new type of Pokemon (so I yes, I don't like what they did with Rotom). Honestly, I think the real missed oppurtunity was making Maganium a Grass/Fairy. Besides Thyplosion is the only pure Fire last evo starter.
Granted in doubles I can Burn Up user being partner up with Protean Kecleon to do some massive damage D:
EDIT: I'm wrong they are typless.
I wish Arcanine didn't have to be breed to lurn Burn Up because I already have an Arcanine all well, I'll miss out on the oppurtunity and just have regular Flamethrower.
I don't think Z-Crystals get eaten up like Gems. Since Z-Crystals stay while Gems are removed after use.