I don't think I'll have a lot more that's helpful to share right now ...
I chose the half my yen bribe.
I haven't done any more, yet, other than what was in the video and then playing to the end of the current content. So far I have only found the Cousins I've found in the video, plus Ban-Ban and Signolo. I haven't tried the quests, other than the Limited to 1 one that I remembered I especially liked.
I've been happy with the whole story so far. I don't think I would like the whole post-apocalyptic thing or what Goro apparently may have done (which I learned at the end) if it were the story to an official katamari game, but it works well in an RPG. I'd just say keep up the good work on the story.
You're the creative inventive one; I don't think I'll produce any worthwhile jokes and such. If you worked in Katamari Forever's Katamari Dancing All Night somehow, I would enjoy it, but I don't know if anyone else would. And you can't go wrong with Disco Prince.