Modern B&W FB glossy paper has a baryta coating, and that seems to be the problem, presuming of course that the gelatin isn't also causing a problem with the wax, but I'd think it would be okay, since gelatin can tolerate high drymount temperatures.

I think your best bet is to coat an emulsion on something like a watercolor paper, as Jason suggests, and maybe something that isn't a gelatin emulsion, so not liquid light, but maybe platinum/palladium, vandyke, salt print, cyanotype, or something along those lines. Albumen holds up to steam, so I think it should hold up to hot wax.