Could you be a little more specific about your goals? It seems you have questions on both the hardware and software end. How large of an area of your house do you want to cover (large room, small room, multiple rooms?).
You mention many possible sources for music but what is your ideal setup? You seem to be implying that you'd like to control the music with your smartphone, but it was pretty vague. Why not go ahead and describe precisely how you imagine yourself controlling everything and we'll see if we can get you there.
As for if your old surrounds will work, well that is going to really depend upon what they are and what kind of sound quality you're looking for. In a nutshell, yes they are speakers, they will play sound.
Do you have any other audio equipment for this yet? Do you have an amplifier you want to dedicate to this, or perhaps a receiver with a second zone or A/B switch?