They have different combat style (Jack and Peros)
Peros can be a pain in the ass for any YC since you'll need pure raw strength (unless you are a Mera user or have a skill which would allow you do something) to get out of his candy and with a bit quantity of it he already trapped all Germa easily.
So most proably is that Jack will have better AP, durability and probably speed (in hybrid) feats since he is a Zoan while Peros despite being inferior in those aspects, his fruit allows him to confront higher lvl characters in terms of strength compared with him.
So it's really difficult to compare them.
For example, despite Jack having that feat against an army of Minks and Peros with only Carrot and Wanda, Peros would be a very tough rival for Jack (tougher than Minks army).
As for CP0, they should be at least VA lvl, above Maynard (one of the weakest). But I don't expect them to be at Peros or Jack lvl, but who knows. They are assassins, they could probably kill stronger characters like them with those abilities (sneak attacks, etc) since only a bunch of people have natural hard skin (Kaido, BM, the guy from Corrida Coliseum, Germa), but not in a direct confrontantion.