Just throwing a nugget in the works.

What if the duel was AFTER yoda, bail and obiwan have the meeting where they decide to go into hiding? Yoda knows through the force that they are the last of the jedi, and all is agreed, but obiwan must find out what happened to anakin. Yoda warns him not to go, and that 'the boy he trained is gone'. Obi wan goes anyway and everything carries on as usual.

Major issue would be the birth of the twins. If there was anyway of having them born before, or possibly born without yoda being there. Potentially lots of back-an-forth.