Plaster of Paris is very good for molds, but sets very fast to use for anything else. I have made many very large mountains using it, but it is a real PIA giving only a couple of minutes to get it on. It does carve well.
On my present very large "plastering project" I ask the forum for suggestions with most replying that brand name "Sheetrock", Durabond, a type of joint compound found good for plaster patching and is very good for large projects. Unfortunately, there was none to be found around here. (Do not use regular joint compound that is used on drywall. It will crack, guaranteed, if used at any thickness beyond 1/4" and with any vibration, etc. Been there!)
After becoming very frustrated, I ordered some Hydrocal online from Plaster.com at a price much cheaper in bulk than any hobby store version (even with high shipping cost). It is very strong and lightweight. I have used hydrocal before in rock molds and it is excellent, but expensive when buying in small quantities and it doesn't take to coloring as some. It does give a better set time when mixed properly.
All the names you mentioned except P of P are expensive to use in large areas. They all work well, but only you can decide what you like to work with.
If you want texture added to your "plaster", go to your lawn and garden place (Walmart) and buy a bag of Vermiculite...it is used in flower pots, etc, to hold moisture. Only use around a 1/2 cup to 3-4 cups of plaster and pre-wet it so it doesn't suck out the water of the plaster mix.