I don't know if you want to add it to the character analysis, but Futo C has a huge item collection box. I didn't really notice it until I started using Reimu and kept missing all the items. Or it could just be my subconcious making excuses for me.
Also, totally not sure, but does Reimu C's gohei change in any way when focused?
Also also, about Futo C changing bullet angles. As far as I know, the only time it changes the angle of the bullets is in stage 5 with the arching missile/suppository bullets (the ones taken from DDC). In danmakufu those arching kinds of bullets use X and Y vector values rather than angle and speed values. Futo changes a bullet's speed value and since the arching bullets don't use speed value they are incompatable, so Futo is basically replacing the arching bullet with a similar bullet that is compatable. Since the arching bullet doesn't have an angle value either the new bullet is given the default angle of 0.
Tl:dr I don't think Futo is supposed to change the bullet's angles, it's probably just a bug.