UPDATE; Just used this procedure to install PIAA H13 bulbs in a 2010 Focus SEL
Procedure worked perfectly.
I used a pair of very small screwdrivers to pop the 4 expansion plugs that retain the top of the grill. I laid one down and used it as a fulcrum and gently put the blade of the 2nd screwdriver under the head of the plug and removed it with no damage.
With the 4 plugs out of the way . . . I was able to reach the clips in the lower portion of the grill. I'm not sure the plugs really do anything. The key here is that there are 4 alignment tabs. A tab on the grill slips under each of them to hold the grill.
Between each pair of 2 tabs on each side is a smaller tab that has a lip on the back. This lip slips over and edge and "clicks" into place.
At first I was trying to remove the expansion plug until I learned it did nothing. The key is to simply wiggle the grill gently and release the tab that hangs over the lip.
I was able to change both lamps in roughly 30 minutes.
Thanks to those who posted the photos and the procedure.