I've written quite a bit about oil based scrubs - if you click on this link, you'll see links at the bottom for many more - but I tend to use salt instead of sugar, for some reason I can't really remember at the moment. I think it's because I tend to have loads of salt around but we don't use a lot of sugar. But then again, I use sugar in my emulsified scrubs, so I have that around the house all the time. Weird...
IPM or isopropyl myristate is a very liquidy ester, so liquid and clear you'd think it was water if it didn't have a label on it. (Don't drink it though. You'll be fine, but it tastes like a light oil would. A bit greasy and oily.) It's a great addition to anhydrous or non-water containing products to reduce the greasiness. It's also a great emollient and makes your skin feel nice after using it. It won't harden up as it's like any oil that stays liquid at room temperature.
So the short answer to that question is yes! IPM would be a great inclusion in an oil based scrub!
No, you don't have to heat and hold for any period of time if you're just using oils. You can put them in the container, add your salt or sugar or other physical exfoliant, mix it togther, then rejoice for you are done!
Pretty cool, eh?