You can plug the propane with anything that is the right size. I use the blanking plugs from Festo but you could just use a crimped tube or a tube with a screw/dot in it.

The kero conversion is simply a heating element that is screwed into the glow plug hole. It replaces the glow plug.

The ECU has to be past a certain software revision version to be able to swap it for kero start but I’m guessing that ones supplied with a P200 will all be able to do this.