As an 11B looking to re-up for Germany, how hard is it to get into the two OPFOR units?

It's not very hard to get Germany as an 11B. In fact, I just locked an 11B1 into a Germany assignment for reenlistment last week.
Also, your window doesn't open up in July. If July is 15 months from ETS you are an FY22 ETS and your window will open up FY21 which is October this year

Hey man, so I PCSed from 2CR in Vilseck about ten months ago. It’s pretty hard to lock in a particular post in Germany. More than likely you’ll get 2CR over Hohenfels/ JMRC. I’m not saying you won’t get JMRC, but more than likely not. Germany can be fun, but be ready to work. 2CR is an extremely busy unit, with a unique mission in Europe. Make the most of your off time, and don’t just drink the days away in the barracks/ housing. Good luck!

I would go for Germany, I spent time, plus I had family there.

It's not hard, especially as a young SPC.
As far as I'm concerned, there are not 2 OPFOR units in Germany. The 2 most common units for 11B's are Hohenfels (this one is the OPFOR) and 2CR in Vilseck. You might end up going to one of these two.