I find saying goodbye awkward enough in real life, and I also find it awkward in comic form.
Given that Hanma's departure could easily last several comics for reasons of feedback on the game alone, I figured the most sensible way to say goodby to Hanma for now was with narration, and, of course, her being the recipient of the first of at least a few hugs from Susan.
As for Hanma having some sort of appreciation for Greg, the guy who invented Anime Style Martial Arts, this SHOCKING revelation can be safely assumed to also be true in canon.
(Also, if I had to explain how Hanma was aware of everyone else, her following Greg around would be the explanation. That could easily explain how she could become aware of pretty much everyone)
What follows will be a sort of montage that's more bonus than actual story (and mostly because I set up they'd be doing that already), but I consider this sort of the "actual" end of the story, so... Yeah, I think what happens next will be assigned the storyline "Goonmanji 2 - Bonus" (thus making me TECHNICALLY right about part 5 being the last part, but not really).