1, Only a couple times, all of them many years ago. The only one I can recall is one that I'm sure I once mentioned on another topic about LBT dreams (you may have to do some digging around to find it). I was more of an outside observer in that dream, but I do recall yelling at Ruby to run for her life and somehow she did exactly that (that may have been the closest to lucid dreaming I can ever recall). The other details, I can't quite recall at this time, but I'm sure it's in that post I made in the aforementioned topic.
2, While I did take swimming lessons as a child and used to enjoy the occasional swimming pool, I lost interest sometime less than ten years ago. As a result, I honestly don't know how well I could swim these days if I absolutely had to.
3, I'm okay with it as much as any other pizza topping. Almost everyone in my family is okay with it, enough so that Hawaiian style (pineapple and ham) is one of the two kinds we always get on every pizza night (the other obviously being classic pepperoni). In fact, we've had pineapple pizza so often that I now find it as more acceptable rather than preferential, not because I dislike pineapple (as I said, I like it fine as a pizza topping), but rather I'd just simply want more variety instead of the same thing every single time.