Thank you for a clever design! I was going to design something much more complicated like your X-axis holder, concerning the press-fit pulleys I got, but luckily you have come up with the idea of switching the side of the Y-axis motor mount.
There is one thing though that I think should be improved. You didn't take into account that when you tighten the belt, the damped motor moves toward the tension vector and the pulley is not aligned properly any more. The belt does not run as smooth as it should and wears faster especially on higher tensions that are needed for clear corners prints. This is getting even worse in the case of the X-axis.
Please fix that or upload the original (vector) model files and I promise to make a fix and publish it here as a remix of your model.
By the way I made the z-axis holder for the damper too. It is not as crucial as X and Y dampers upgrades, but definitely improves both silence and smooth z movement. Here's the thing: https://www.thingiverse.com/thing:3383222