I'll test out the offensive Accelgor set for you (I personally think it has potential, its so fast!)
I'd honestly straight up slash unburden as an ability choice. Both of them provide Accelgor with negligible upsides, but I can see why someone would choose either abilit. Go ahead and mention Final Gambit in AC (this might change to an actual slash after testing) If Final Gambit is used, you should mention running max HP to maximize its effectiveness. On the Suicide Spiker set, feel free to mention Giga Drain in AC to combat Blastoise as a potential rapid spinner. You won't kill it, but you'll do some respectable damage.
Hitmontop needs to be mentioned in checks & counters, because it can kind of switch in for free and spin.
Don't forget to implement the other suggested changes!