Unpopular opinion: genderbent Midoriya isn’t slim. She’s definitely jacked, but the kind where you don’t notice until she strips & flexes so she just looks a little fat (like her mom) when she’s not Unleashing The Beast. Also, could crush a watermelon with her thighs.
Todoroki, however, looks like a runway model who does MMA in her spare time. Seems too thin for fighting but is actually all made of wiry muscle. Bakugo is just built like every female jock ever.
Boob wise you’ve got Midoriya up first around the D range, Bakugo second with B or maybe C (maybe with those boobs that are super uneven sizes), & Todoroki with Literally None to Speak Of, because when I say runway model I’m talking Haute Couture, not Victoria’s Secret
Additionally: Midoriya has an adorable pixie cut that’s maybe 1 or 2 inches longer than her canon hair cut, Bakugo has a ridiculous 1980s ponytail (she wears it long so she looks less like a carbon copy of her mom), & Todoroki has a bob that’s a little past chin length, probably around mid-neck, it gets in her face a lot but she never wears it pulled it back because of the scar (girls are more conscious about that sorta thing, natch).
That, or she wears it long (shoulder blade length) with bangs that brush down a little below her eyebrows. It’s probably the kind of silky-straight that slides out of hair ties and braids, though, so I’m thinking the shorter cut would be more convenient.