Can I also use this system with other audio sources such as laptop, DVD player, etc.?
Yes, the LR-100 receiver/amplifier has auxiliary inputs on the back. You can choose to mix the aux audio with the transmitter audio or have the transmitter audio "duck" out the aux.

Can I customize a Listen Tour System?
All Listen Systems are completely customizable for any size group.

What's the advantage to purchasing a system as opposed to separate pieces?
Ordering a Listen System is a convenient way to ensure your order includes all the necessary components. While there is no price break for larger volumes, you can add or remove items without a price penalty.