PB, those EVs aren't very good for Little Cup. It (EVs at level 5) confuses most people, hell even I don't know how EVs at level 5 work. But I don't need to know, since I pay attention to how much EVs are needed to raise a stat when it comes to PO. It is different for every Pokemon it seems, so it requires moving the little bar. You'll want to run these EVs with Mankey:
EVs: 36 HP / 196 Atk / 76 SAtk / 196 Spd
This gives you max Attack and Speed. It also gives you one point in Special Attack (which is the most you can get out of Special Attack with max Attack and Speed) with enough EVs left over to get a point in HP.
As for Nature, Item, and moves, everything is exactly what I would've put, except maybe for Earthquake. I might've gone Thunderpunch to take down Mantyke and Frillish, who might cause more trouble than Litwick.