Giovanni appeared in the World Tournament in Black and White 2. So that probably means that he'll be the Viridian Gym Leader once again. As for 3, there's not really any "proof" that Giovanni was ever the leader of Team Rocket. You remember in GSC where Erika mentions how Sabrina and Surge used to be part of Team Rocket but they weren't prosecuted or anything because there was no proof, according to the chairman? Erika stated herself that she even tried to have the two arrested but failed because there was no hard evidence to back up that Sabrina and Surge were affiliated with Rocket. It'll probably be the same for Giovanni.
Originally Posted by Kimchu
Image removed for making the signature too tall, too wide and over the 150,000 pixel limit.