I remember seeing a study recently that showed fish oil taken w/ CLA enhanced it's fat loss properties. It didn't mention if they were in softgel or liquid, but that shouldn't matter, since they'd mix up in your stomach, anyway.
I've never read that sesamin oil shouldn't be combined w/ either of these two. The only oils I've heeard not to take at the same time are flax and fish, since they'd compete for absorption. I would think it's fine to take the three oils you mentioned at once.
As to liquid fish oil, I've used a lemon flavored liquid fish oil from Vitamin World. It didn't taste bad at all, to me, and it was really well priced.