It is basically what Loth-sworn do right now. They can be anything but they believe in Lolth, so they get unique options for that. But I guess that would make the "race" redundant if they added anyone to select a deity.
Yes, that make no sense.
Drow are a race, not a religion. Plus both drow "races" are mechanically identical.
All chars should be able to select a deity, but no race should be defined by their religion.
suggestion:
- Each char should be able to select a deity (or chose to select none)
- By default only the deities of their race are shown.
- You can select "show all options" if you want a dwarf who worships an elf god or a halfling who is a fan of the gith lich queen.
Prof. Dr. Dr. Mad S. Tist 
