With regards to populating the drop-down in vRA, this might help:
I would suggest breaking up your question into smaller pieces.
Did you get this figured out? If not, let me know and I'll see if I can help explain it easier.
Hey! Sorry I missed the reply. Here is where I ended up with this.
It seems like it is more complicated than it needs to be. If there is a better way to accomplish this please let me know. The only way I could sort out how to get this going was getting it into an Action and then using the Predefined list of elements to populate it. The scripting is me piecing together a few people's code. If there's an easier way to accomplish that I am all ears.