However, on the bearing - https://www.amazon.com/gp/product/B007HS0MHO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 is nearly the same size as the one you're using. It has far more load capacity than you'd likely need for far heavier robots. Would require some futzing with the design to incorporate.
You could also use the printable slew ring https://www.thingiverse.com/thing:2375124
I've also always been a fan of the FRC16 style bearing set up with a ball groove on the bottom and a top piece with nylon as a bushing surface. The bottom balls provide bearing functionality and the top nylon provides retention. Let's you have more material retaining the balls.
Any chance of discussing how you found the belt path? I'm going out on a limb and saying SW 3d curve and path length constraint?