Michael, pry away. It is a split cap. You can see a slit in the plastic that runs to the metal arm. The cap just pops off - screwdriver under the cap and it will come off. When you put on the Homelink visor, you won't need that cap anymore. So even if you broke the cap, it doesn't matter.
Once you get the old visor off, you'll have to really dig to get at the electrical connector. It is pretty well glued to the back side of the headliner. Just pull, it will come loose. The headliner is very flexible also, so you can get your fingers up in there.
Odd, I got a PM from somebody asking the same question about the same time you posted this. What's the chances, two people needed identical information at the same time?