The manikin claws inherently have bleed on them prior to any infusion. Infusing with bleed increases the bleed output with only a slight decrease in the physical damage output.

Pro tipp: Let the poison bug on the ledge alive and use it as a brake for your jump. It will be "confused" by the jump in it´s face and you have time to roll away and dispatch of it.

why does it say they do strike?

Confirmed: on xbox one sotfs edition the claws are slash not strike.

The Manakin Claws drop from more than just those three Masked Manakins, at least on PS4. I received one while trying to get their gauntlets. It was dropped by one of the three that attack you above the Central Earthen Peak bonfire, up the stairs and up the ladder, one of those three dropped it.

Power stance two of these, add a Stone Ring + Engraved Gauntlets and you're good