Beedrill can OHKO Amaura with Rock Smash [Base 90 Atk and x4 effective]. It outspeeds Tyrunt and hits it hard with Rock Smash if it's got Swords Dance; and OHKO's with SD.Uhhh... Beedrill does not beat Grant. You are utterly mad if you think this is the case. Rock Tomb and Take Down utterly ruin Beedrill of the same level. After reading your comment I was doing calcs and if Amuara uses Rock Tomb first, you lose. Badly. Like, it deals 60%+ to you. And thats if you are the same level as Grant is. I have no idea how you managed to beat Grant with Beedrill honestly unless the AI was doing something seriously derp. Not arguing with D placement, but I think he's lucky to be there.
Carbink is definitely D material. It has offences unlike Shuckle and it can actually hurt stuff with Ancient Power/Dazzling Gleam. It was my go to mon for me against Team Flare too, hitting pretty much everything they had decently. The only thing is its slow and takes forever to level up.
Beedrill outspeeds Amaura and it doesn't always use Rock Tomb; hence why I said it is risky. Beedrill survives Take Down; and that is all it has to do since it proceeds to outspeed and OHKO everything else. The AI is not exactly great. Especially with the first two GL's. [For example; Viola usually spams Infestation regardless of anything else; be it a x4 resist that Tackle would hit harder or not. Grant tends to use random moves too; but not as badly as Viola.]
That's why I said a sweep is a risk. There is a strong chance Amaura will Rock Tomb and either OHKO you or drop your speed so you can't sweep. But Beedrill can easily defeat Amaura at least with Rock Smash; and then deal hefty damage to Tyrunt.
I think Carbink is more akin to most of the E pokemon than the D ones personally. It's slow; it's multi-hit KO'ing everything and slow to level.
And if it wasn't for Swords Dance Beedrill would easily be E. But Swords Dance and good TM timing make it a bit more useful than things like Sentret.