Same as the majority already said. Whiskey Peak Luffy shouldn't be much stronger than the version who beat Arlong, yet he and Zoro didn't even treat Mr. 5 as worth acknowledging during their scuffle. Arlong wrecks hard. Even Hachi and Kuroobi probably low diff him too, though I'd imagine Mr. 5 could beat Chew without much problem.
As for Mr. 2 VS Arlong, I'd say Mr. 2 wins fairly easily. He was shown capable of damaging a foe that Impel Down Luffy needed his Gears for and wasn't implied to have become any stronger during his imprisonment.