While it's technically unconfirmed, gameplay shows the Predator's weapon/gadget select has 7 slots, with only 3 of them being used in everything that's been shown so far (wrist blades, plasma caster, medicomp), so it's a fairly safe bet we'll be able to choose our weaponry one way or another.
Likewise while we haven't heard anything yet about alternate skins, Friday the 13th had practically every Jason skin you could think of, so it's also a pretty safe bet we should be getting some different Preds to choose from too.