Hi pepperi! The only one I have tried is BBs Passionfruit Rose, which is a flavour oil and soaps wonderfully! It is also great in an anhydrous body butter I make. This wasn't trial and error - my supplier worked out it was okay for other applications. I have used flavour oils in MP base with some success but I mostly tend to use the soap-safe ones. My advice from my supplier was that it is best to leave well enough alone! She has tested others in CP with no luck. I did use a mango flavour oil in my body butter once and it ended up forming hard grains which got worse over time. The same formulation (from the same batch) without the fl/oil was fine.
I've used those little tiny flavor oils (the ones that you use to flavor hard candy) in my sugar scrub. It worked fine with that, but it was just like 1/2 cup sugar and 3/4 cup olive oil. I only had to use a few drops.