Reply to Modular setup soundcard queries!

Hey guys,
I'm planning to buy a mixer, F1 and XI to replace my S2. I realize i need a soundcard to connect the mixer to my computer. The question is, if i'm using 2 main decks and the remix deck thru the F1, do i need anything more than an Audio 2? Also, would it be possible to connect the mixer to my computer using my studio card, which is a Focusrite 2i2?

Thanks in advance!