Haha, I this roleplay thing all the time.
Ever since I actually understood how to spawn peds like Gary and Pete, every time I see either of them I'll stop and have a 'conversation' with them. When they say their goodbyes I just go after them, like they're walking together or something. :'D
On the current game I'm playing after Chapter 2 I made Gary a Prep, because, I guess he had to hang out with them to get them on Jimmy's bad side. Right now I'm on Chapter 3 and did the same with the Greasers. Wonder what to do with him during Chapter 4, though. Maybe disable him? Then during Chapter 5 I'll make him an authority member.