just as Nick and Renard became allies through confrontation. Have Elizabeth and Kelly need to join forces. In the need to protect Diana. Consider the royals now know Kelly has the child. There is Chavez and her group. Kelly is going to need help. Elizabeth is the best choice. See saved Nick so she is not Kelly's enemy. Kelly does not like hexenbiest, but will work with them to achieve a goal (worked with Renard to save Diana) . I could imagine the shock Adalind would have when faced with both Kelly and Elizabeth standing between her and Diana. would be enough to cause Adalind to become a double agent. giving her some sense of redemption. Remember she has a lot to atone for, she sold her baby to get her powers back.
Embrace your inner Biest..... We all have one