The protagonist is so silly and adorable.
Is the protagonist in sun/moon more expressive than in the previous gens?
Or are all these doujins just wishful thinking?
Honestly, she's so unexpressive that it's kind of bizarre. She has one single smiling expression that never ever changes, no matter how desperate or touching or joyful the situation, and it started to look almost creepy and empty the more I saw of it. It's been speculated that she's actually a ditto mimicking a human, and the theory is fairly convincing based on her creepy smiling face alone.
You can kind of piece together the cheery, energetic, life-loving character that's usually portrayed in doujins by looking at how other characters react to her, because everyone else responds to her like she's the doujin character, and nobody seems to notice that she's actually a creepy smiling doll monster, so... She's implied to be silly and adorable, but you kinda have to imagine it for yourself.
Not that unexpected. Tsubasa's behavior and memories in the first chapter made it clear that she had some issues with her family, and had been treated violently in the past. That was clearly going to come up sooner or later.
Unless you mean the out-of-the-blue question about her being a prostitute based on speculation from strangers. What kind of world do these kids live in where two high school girls and a man walking together are assumed to be part of the sex trade? I've heard that teenage prostitution is common in Japan, but don't girls have fathers and other male relatives? Being accused of prostitution by random gossip seems to be a common plot device, so maybe it's just one of those things authors throw in for the sake of drama, or maybe high school gossip really is that awful.
Japan had a very bad problem with females joining the sex industri at some point. I dont know if it's still as bad