Franklin stays hidden (for now). He looks (but does not touch) if he can figure out how to release the wyvern. Perhaps some kind of lever or latch mechanism?
Franklin was listening at the north door. He thinks, "Sounds like these people need allies," and opens the door, so the party can have a conversation with the un-charmed fighters. He's still invisible, so the fighters would see the door appear to open under its own power.
Oh yeah, Franklin almost forgot! He also looks for any kind of runes or wizardly writing on the door. If you think it's a good idea (and assuming we can get past one or both of the doors) Franklin is willing to have an invisible snoop-around. He'd be looking for obvious signs of Ozminster's moral c...
Franklin agrees with Maloof that somehow profiting from the Thoth/Ozminster conflict seems like the most entertaining option. Hearing Ozminster's side of the story might be a good next step?
Franklin isn't a thief, so he definitely doesn't try to steal the wand from the wizard's belt. He leaves his dog Sconces with Balbo and Drogo and casually steps into the room with Maloof. He acts naturally and watches the wizard's eyes. If the wizard makes eye contact then Franklin will infer that h...