To turn an individual speaker on and off, all you need to do is wire the switch in series with it - it's that simple.
An LED requires a resistor in series with it to limit the current otherwise it will blow up, for 12V, use a 680R resistor.
Your verbal description is very confusing because it isn't clear how you want the switches to control the lights.
You can get double pole switches which are just two switches, in one package, operated by one lever. If you need to switch two things at once, they're your best bet.
**broken link removed**