Pretty much! Our main concern with homebrew was creating a wholly different class with no set rules/standards. We want everyone to be on relatively the same page - narrative aspects of your character can be entirely up to you, though, because they really don't change the powers granted to your character. So you can come up with your own demon, or pick one from a list, or do whatever narratively is most fun to you! As long as you stick to the set power-list of warlocks, you can essentially do whatever you like. :)