From what I know of the PRC, you can add selectable feats to any class or prestige class, so the raw answer of it its possible is yes. However it might not be desirable because those feats will always be selectable from that class.
For example, to make Warlock-only feats selectable from Acolyte of the Skin, those feast have to be added to Acolyte of the Skin. Anyone taking Acolyte of the Skin from then on, even if they are NOT a warlock, would get those feats as selectable.
I'm sure that's why the warlock feats are not already added to the several 'general' prestige classes that can advance warlock.
So, its unlikely to be included in the PRC directly, but if you wanted to do it for yourself locally its possible to do via editing the 2da files.