RockportMen's Junction Point Slip-On

Is the insole removable or is it glued in? I have tendinopathy and need to be able to remove the insole, place cushioning on it and replace it.

I have a high instep, is there a fair amount of flexibility in this shoe?

Is shank metal? looking for tsa friendly shoe.

Why do you charge more for a smaller size than a bigger size, that takes much more material? How does that make sense?