1) Who the fuck that isn't specifically looking for such signs for such reasons is gonna notice the bloody color on a single fingernail?
2) Giving friend chocolate is also a thing on Valentine's Day in Japan, I think we've all seen enough rom-coms to know that works, so once again her giving Futaba chocolate doesn't inherently mean anything to someone not thinking it does.
3) Yes, cuz making cute boys crossdress isn't a thing typically seen in animanga.
4) Fine, I relent there is nothing for no one to say in that regard, but that fact we had to into the 120s for something substantial just proves my point. Unless you were thinking she was gay/bi from the start for whatever reason, no normal person is gonna think she is from how a good chunk of the series doesn't do anything that really is thought of as romantic, especially when you throw Yuuto into the equation.