The S2 is a great mid range controller, it can do everything you will need to start with. I would advise to purchase this on its own 1st and push it to its limits. Once you have mastered it, you will have no problem including any other MIDI controllers into your set up. If your laptop has limited USBs you can add a hub in order to get everything linked to the laptop.
Use 1 piece of kit until you fully exhaust its potential. Once you know what it is NOT capable of you will be able to make a better decision as to what your next purchase should be.
Learn to crawl before you walk!
HTH