Can I make a full face prosthetic for an actor with facial hair?

Hello! Below are pictures of my actor's beard. I want to make a full head prosthetic appliance for him to wear that shows his face swelling up as he is filled with worms on the inside. I've been developing a way to pump a silicone appliance full of a worm / water solution. I have a post that goes into more detail about that process. Now I'm trying to decide how to deal with his beard and mustache. I've been imagining I would punch hair into the prosthetic to recreate the actor's hair and beard. But will I be able to apply that finished makeup onto the actor without him shaving his beard and mustache? I imagine I could trim and then comb down his mustache and beard hair with petroleum jelly to give me as much clean skin as possible around the mouth and nose for laying down and adhering the edges of the appliance to his skin, but I imagine it will be very hard to get enough surface area of silicone touching skin if he's got a mustache and beard in the way. Should I ask him to shave off his mustache and beard for this application? Or trim them significantly, like with a #2 razor? He's a principal character in the film but the way we're shooting this, the prosthetic is the last thing we shoot, so in theory we could shave his beard off entirely and not have to worry about continuity because we won't get any other scenes after this. Just wondering if there's a general protocol for making prosthetics for characters with beards in a situation like this where you want to match the hair look of the actor without makeup to the hair look of a prosthetic for them to wear? 

Thank you for any thoughts! 



Here's pictures of a speed sculpt I did - the finished appliance would have a shape similar to this: