I think All Loves would be a nice category to add. It might be too similar to All Hamchats, but it would end at the long cutscene when Harmony congratulates Hamtaro and Bijou, which is a really nice spot to end a run.

I was also wondering what people thought would be good 100% requirements. I was thinking all loves, all hamchats, all songs, all gems, all accessories, and all costumes. Thoughts?

I would say that all loves, all hamchats, all songs, all gems, and all costumes is doable. I have no idea if the all accessories is even possible. Unless you have a way to duplicate the five star gems then it is not doable, to my knowledge.