I am trying to go to TPA in a few weeks. I will be flying from WAS and my GF from DEN. I am interested in getting us on the same PNR using miles for her ticket and paying for mine with $$.

First of all, is it possible for us to be on the same PNR like this?

Second of all, if I book her on DEN-IAD-TPA-IAD-DEN and I jump on the IAD-TPA-IAD legs with her, can I get her in E+ the whole trip even though she's not elite? What if she goes DEN-TPA-IAD-DEN?

Third, if I book a standard ticket with miles (40K) for her, what fare bucket does that drop her in?

Haven't had to do anything like this before, so I am curious if anyone has any advice on what to do to make this happen.

Thanks!