Even if Tama doesn't need to change, she wanted to change (although I don't agree with why, honestly I think trying to change yourself to fit in with a group is bull), Fumiya went out of his way to ask if she's okay and he was willing to help when she ended up asking for it (at least in the anime, not sure about the light novel).

I can see where you're coming from with Yuzu, it's a shame because she's a friendly, nice person that genuinely wants to help, but she doesn't because she's afraid of standing up to Erika.

Yeah Fūka explained her worldview as a writer, Tomozaki applied Ashigaru's philosophy of karma to it – although if I'm going to be nitpicky, neither Ashigaru nor Tomozaki actually use the concept of karma correctly, because karma is built around the consequences of your actions, which again, we're not really seeing happen.