ReimuA's bomb needs a bit more range, and a bit more oomph to deserve the range and wacky movement you get during it. Her shottype is good enough as it is; possibly too good. Having both an omnidirectional superhoming shot and a strong homing area-specific shot gives you access to tons of stage planning and in general is pretty game-flattening.
ReimuB's needles need to do more damage, maybe. Everything else is fine.
MarisaA is pretty much fine as she is.
MarisaB's bomb needs to be massively nerfed on the invul / bullet cancel (i.e. the period it's on screen), and the power item spawning. I think it's a good utility bomb and could be done well if its overwhelming brokenness is fixed. I currently use MarisaB and feel incredibly guilty every time I bomb. Her shots are fine.
SakuyaA's focus shot is cool, but much too powerful for the utility it gives you. Homing, enemy slowdown, explosion damage? This shouldn't be nearly as strong as it is. On the other hand, her unfocus shot you might as well never use because of how overwhelmingly better her focus shot is.
SakuyaB needs some buffing. The unfocus shot is actually fine (as it is with A), but her focus shot is in dire need of help, especially at lower powers. I think it's intended to give you a Galuda feel to it, but at this point it's more like you're using Ageha's shot with Tateha's rapier. The shottype itself is great (a bit of coverage on her sides and behind her would be nice), but it's so underwhelming I left her for MarisaB just because her shot actually has some power behind it. I think it would really benefit from additional shotgun damage as well, which would pair nicely with her bomb, which is also super cool. I'd say the stars you get back might be better off as just two, but really it just needs to be balanced against how much MarisaB gets.