In my opinion the use of PVA isdependenton the paint. Wax provides slip but is unable to block reactivity. If your paint is chemically reactive with your resin, it will stick with just wax. PVA is able to block this reactivity. Unless you do some testing with your paint and the resin you can't know the outcome. The safest bet is to use PVA. It's best to use a wax that is designed to work with PVA. Nearly any wax will work, but some can cause the PVA to fish-eye on the surface (can be worked around by using light coats). Part-all Paste #2 and Part-all Film #10 play nice together. If you want to retain the finish of your plug you can use a semi-permanent like Frekote. The downside to Frekote is that you need to use a 2 part catalyzed paint on the plug. The solvents in the Frekote will etch single component paints and cause a stick-up.
I would start the molding process by brushing on a surface coat. It can be made by adding 30% West Systems 404 and 7% graphite powder by weight to a batch of laminating resin. The purpose of the surface coat is to insure, if properly applied, that the mold surface will be void free. The graphite powder will make the surface black and increase it's slip. Once the surface coat tacks up (tacky to the touch but won't transfer to your glove) I start by adding 3 pieces of resin saturated 12K carbon tow to the corners. This creates a fillet to strengthen the corners and help prevent the fabric from bridging the corner. I usually start laminating with 2 layers of 1 ounce, then a few layers of 2 ounce, then a few layer of tight weave (56x56) 4 ounce, then some 6 oz. You want to alter the orientation of your layers to maximize the stability of the mold. If the fabric all runs the same direction the mold will be more prone to warping. The thickness of the layup is really dependent on it's size and the part processing. Molds that have large opening like a cowl mold need some good thickness to hold their shape. I consider a 60 ounce lay-up to be the minimum.