Welcome to the wonder ful world of Constrictor!
For number one I would suggest Photoshlop. Its a little high end, but that's just how we roll around here.
For number two I would say Audiggity.
It has all the basics for mixing sounds.
Not sure what to tell you to use for number 3.
Safe to say there's tons of options out there.
Why I've even see a Itube with someone using their Wephone.