So, both of the Keystones belonged to Platane-Hakase, right? He kept his Gablias Mega Stone and Keystone to himself, right?
Nah, Platane only had one! He asked ~Mysterious Bursyamo Mask~ to lend him his KeyStone during the fight against Team Rocket, that’s why both Kojirô and him had one at some point, when trying to make Gaburias mega-evolve :3 Platane gave back the other KeyStone after the battle (and got his own KeyStone back), and smelled ~something familiar~ on it (so he knows about Limone, now, he went to see him at the end of the episode and to ask him to help his research). Carnet’s voice was just a short flashback at the beginning, when the kids heard about Mega Evolution. Platane thought about Alan when the kids were there but didn’t mention his existence to them + had flashbacks with Alan later, when getting worried over Gaburias (!!! IT WAS ALAN WHO BROUGHT THE WILD THING TO HIM!!!)So yeah, Platane kept his stones (Mega Stone + KeyStone) and, as usual, I think Satoshi himself showed 0 interest in Mega Evolution /o/ (Eureka was the most excited, I thiiiiiink)