I have not been using the tadpole and basically had only some class or background statement options in conversations, which also happens with the companions. Also as far as I understand it the tadpole is available to every character that is part of the playable group. So nothing about it would be limited to Tav.
I was hoping there was some special Tav-centric explanation for why everyone gets dreams when Tav uses the tadpole and doesn't get them when Tav doesn't. I guess that didn't pan out.
