Harvest A+
KQ is S, solid A~ Stand by itself (good speed, good physicals, etc) has a good offensive ability that can be used to one shot those above it, erase evidence, and even set traps (making a bomb and if someone touches that bomb, transfer the charge, wouldn't be hard to rig a trap to kill a enemy if you know where they're going or places they might go, one set, the bombs have planetary range, can also be used to offset the low range by using projectiles). Also works on destroying attacks and shit.
SHA is an infinite range automatic Stand that can put the strongest Stands in the verse on its ass and probably has the highest durability of any Stand making anything but hax useless, it does have a weakness in the infrared thing but not many dudes gonna be able to figure that out in time if at all, and if they could, might not be able to do anything about it depending on where they are or their power.
BTD is prep god, instant win 99% of the time if you aren't brain dead, Kira was braindead, hell he LITERALLY won but still lost, and that was with him using it just ok.
Downsides obviously include bombs can hurt you too and BTD can't be hosted on a Stand user but they're not enough to effect him much. Full package is solid S, SHA and BTD really good, hell SHA was only beaten because Josuke hard counters KQ in every aspect.
Cind is D, literally only good at one thing, it has some fate manip though but it's so hyper specific it's like whatever, doesn't even help you.
B, low power for a power type, but ok speed and 3 Freeze hard incaps 90% of the verse, at it's highest you'd need like Class M to get past it, though the short range is meh, hurts it quite a bit, the fact he has to enter CQC to use his win condition while either being out ranged by most Stands and the Stands that he doesn't outrange would fold his ass is kinda a huge downside. He's a bro tho so there's that.