I think the other route is as Shannon Briggs.
Briggs fights in June for WBA regular, assuming he wins, he would be ready to defend again around the time Haye is back. I don't think Haye or Briggs will want any tune up fights with the clock ticking.
Briggs gets his pay day he's been chasing for all this time and a crack at Haye,assuming Briggs doesn't take Haye out in the first four rounds that I predict he will try too. Haye gets a version of the world title which is more of a key to unlocking one of two fights he's wanted. Madatory for Klitschko rematch, or maybe the biggest domestic heavyweight fight ever against Joshua, and also gets the chance to become heavy weight champion like he always said he would become again........ then he can sail off into the Miami sunset and we can all move on.