Unfortunately I do not have Substance Designer. Thank you for linking it though. I may have to get it if I can't find a workaround for this. Here are the diffuse maps. Legs Diffuse Body Launcher
Currently there is no merging feature in Substance Painter, if you have Substance Designer check out this video: https://www.youtube.com/watch?v=HMP2xpGHimY Could you perhaps post your diffuse map here? You could be accidentally baking in the models diffusion.