I've also thought of a few ideas for the voices I imagine that Momorasaki, his partners and Pyonchi would have, specifically using voices of characters I like from other series.
I imagine that Pyonchi would sound like Yuffie Kisaragi from Dirge of Cerberus or Rebirth. I mean, just watch any of the scenes in the aforementioned games where Yuffie dramatically introduces herself and tell me that Ogerpon wouldn't do that. They both have the same vibe of wannabe heroes who over-embellish their strengths and who may have a penchant for theft.
I feel like Momorasaki would have a similar voice to Shinji Ikari. Whether it's Megumi Ogata's performance in the original Japanese or Spike Spencer in the ADV dub, I think both would work for him. After all, I do feel like they are similar characters in the sense that they are timid, often seen as cowards, but still try to do the right thing.
Midorinu would sound like Zack Fair, specifically his voice in the original Crisis Core. Because dog.
Mashiraoi was a bit tricky to figure out, but I eventually went with him sounding like Ienzo. I specifically thought of his English voice because I don't know what his Japanese voice sounds like, but I'm sure it also works. They're both very intelligent and cunning, but would probably be really cool to hang out with.
I had a couple of ideas for Kigisukuro that I think could both work. My original idea was that he would have Kyubey's voice, either English or Japanese. Then I also thought that if he had a deeper voice, then it would probably sound like the Pure Resentment voice option for Junko or Tenet-Breaking Hermit voice for Seiga in Lost Word. I don't have much of a preference between these two.