Swallowing is completely okay, but try not to do it unless necessary. Don't have the intent that you're not going to be able to fall asleep if you swallow even once. You can keep your hands anywhere you feel comfortable with, you want to feel cozy so you fall asleep easier. Like others said you don't want to aim for sleep paralysis, it's just a side effect that sometimes occur when trying to WILD. In WILD you transition straight into the dream without the paralysis part, so you shouldn't aim for it at all. But if you get to the numbing part ( not paralysis ) and it helps you relax and fall asleep easier, then aim for that part. When I used to WILD I let my mind wander and simply stayed lucid instead of trying to reach lucidity. You could try it with that mind-set too.
I think WILD is mainly done on the back, but I don't see why you shouldn't be able to do it on your side. I do it on my back too and it helps me stay focused, in fetal position I just feel too sleepy and I need "luck" to enter the WILD state. You could try to do a reality check everytime you wake up and make a habit out of it, so you won't miss any false awakenings and become lucid with them.