This is totally ending up a legendary moment in their cosplay community. I'll call it:
Ano Hi Mita Cosplay Hime no Namae to SNS mo Bokutachi wa Mada Shiranai.
"We Still Don't Know the Name and Socials of the Cosplay "Princess" We Saw That Day."
Marin getting scouted might be a major opportunity for a lot of cosplayers, but I think it doesn't line up with her main motivation for cosplay, so she won't take it. She loves it as a hobby, and even more she loves doing it with the guy she loves. Going pro means leaving all of that behind, and being a professional also means having to do things you don't want to as part of work: as a hobby she can freely choose who to cosplay, but as a pro she really can't refuse being told to cosplay some character at the risk of losing future opportunities, reputation, and money. Someone else other than Wakana will be making/buying her cosplay outfits too unless they hire him as well (I doubt it, agent didn't even ask about the costume).
Man, that tinge of jealousy stung a lot more than I thought for Wakana. But without his thoughts I really can't tell for sure if it's still jealousy or his old nemesis low self-esteem creeping up. This is setting up for some conflict that can be resolved by them talking. The pained look on his face stopped Marin from trying to talk to him, but I still think she should've at least tried to reach out. Maybe she's trying to be extra considerate but this might not end well the longer they don't talk.
In the meantime, I'm sure that author will see the amazing cosplay of his character soon. So we've reached chapter 100, and it's got a bit of that cloudy, overcast day feel, perhaps even gloomy end to it. Maybe 101 will be a banger, well I hope it will be.