[Meta thread] Iron's PokeRole Adventure: The Skull Ruins

[Iron]

(Then can Terra simply pick up the Pokémon and wait for the right moment to toss it out to try and catch P-Bulba. ? Should be possible, right?)

I think the main question is if PB is caught, would it have Nathan's OT since Terra is only helping or Terra's since ge made the capture?

It depends on who owns the Pokeball that's thrown. Using a Pokedex you can transfer ownership of an unused Pokeball as a trainer action. Or just exchange Pokeballs.

Another mechanical nitpick/question: would a sound based move also bypass Tangled Feet due to the nature of the attack?

Only if it's a spread move. Something like Supersonic still has a shape and can be avoided just as easily as any other attack.