To FF or not?

I currently own a Fuji X100 as my walk around camera and would like to buy either a 7d or 5D II As I will use it 50/50 for photos and short filmmaking.  A few questions:

1. If I use the 50mm 1.8 EF lens on both cameras, will the image and video quality be much better on the 5D?

2. Will the FOV be 50mm on the 5D even though the lens is not FF?

3. What is the least expensive FF lens for the 5D?

4. Do you feel if I won't be able to afford a FF lens for a year, it will be a waste to buy the 5D?

thx