Doug is a pedophile.
This would certainly explain why he's not allowed to live near a school. It may be that not all of the material in that Porn Stash of his is of adults...Bug’s new owner and Emma are friends or at least neighbors.
Hopefully if her parents allow her around dogs still, this could let Bug and Emma have a sort of indirect reunion and bring some closure on Bug’s part.Doug's ex-girlfriend will move into the city, discover Reggie, and adopt him again.
As a way for both of them to have a happy ending, assuming Reggie will eventually get tired of stray life and want a home again.