Raphael Adolini 1715 on Greyback's pistol
Prey is set in 1719
A bit weird if there's zero connection...
If they're ignoring the DH short, Raphael Adolini could just be the gunsmith's name and it wouldn't be that odd for a French trapper to be using a pistol made by a gunsmith with an Italian name.
This could leave room for Feral to be implied as young Greyback.
Trachtenberg says Feral could be from a different hemisphere. Relative to Jungle Hunter, Crucified, the Super Clan and Fugitive...Feral, Greyback and at least some members of the Lost Tribe have a noticeably more tribal, almost shamanistic aesthetic.
Not saying there's def a connection as I'm just speculating, but think there's room for Predator 2 and Predator 5 to be linked somehow.