Mechanisms and Reaction Coordinates

I think my mechanism for part a is correct. For part b the reaction coordinate, I usually just determine which side of the reaction is favored (I use pKa and strength of acids to do this). How do I determine it in this case? Do I use the percent yield info given? Thank you

I think my mechanism for part a is correct. For part b the reaction coordinate, I usually just determine which side of the reaction is favored (I use pKa and strength of acids to do this). How do I determine it in this case? Do I use the percent yield info given? Thank you