The whole point would be to have the shows overlap to underscore Jimmy's fall from grace, so to speak. Obviously it would come after we learn Kim's fate, which is one of the driving storylines of BCS, IMO.How could WW interact with Jimmy/Saul in BCS when we know from BB that he meets Saul for the first time later. You see the scene in BB where they first meet.
Honestly, I'm also anxious to see what becomes of Jimmy/Saul in Omaha. There's a reason they begin and end every season of BCS with the black and white footage in the flash forwards.