Depends on what you want to do with it. You can definitely run more interfaces (I use three) but will they do what you want? hard to say, cuase we dont know what you actually want to do!

Yes you can.

To stay in Cubase, there's an option of using this driver Asio4All which will allow you to use different input/outs on different sound cards (mutliple audio interfaces). I believe ASIO4 all utilizes the windows WDM drivers and wrap them into an ASIO, so the ASIO limitation is circumvented.

ASIO restricts the use of more than one sound card (The only software that I'm aware of that will allow this in windows without extra work is Sonar by cakewalk. When I used to use cakewalk, I was able to utilize two different sound cards by two different manufacturers at the same time. For this to work you need to use WDM drivers because ASIO won't allow this)