I apologize if this has been covered here but I am looking at buying the Inspire V2 single remote setup for now and if I wanted to down the road buy another remote to create the dual remote setup. Is that possible?

In short... yes.

Yes, you have to set the second controller in slave mode. Here is very well explained

That is the way I did it, there were no issues.

Yes sure! That is gonna be absolutely the same as double remote version