Thank you for your reply!!

I am able to get this mesh after changing the mapped mesh type to prism under multizone method. The Orthogonal Quality value is 0.11. However, my mesh quality metrics were better with the previous hexa shape. 

How do I make sure that I am getting at least 3 elements across any gaps? 

I am running this simulation with FEA and CFD. For the FEA, does it matter more for my quality metrics to be optimal or tri element (PRISM setting)? 

Please help!