Mold question

I made a plug for a modified bumper for my car. It includes parts of the stock bumper and some modified parts as you can see. I will be coating the plaster with epoxy resin, then waxing the entire bumper, then PVA. The plug includes the black diffuser at the bottom. I will also be using clay to taper the sharper angles to aid mold release. My question is, can this be done as a one piece mold? If not, how many pieces and how should it be parted? Thanks

Dave