SANUS EFAS-B1 EuroA/V Shelf/10-95

How much clearance between the floor and the bottom of the shelf? looking to put a 7.5 inch avr under it

does this have a hole in the back or does it use the newer clips for cable management. The picture and discription are conflicting.

is this safe to attach to the full sized stand? I only see pics of this plus the base

can i screw this into the other base that they say will work cant remember the name