would a conventional chain drive be more effective than a resilient toothed belt for the backlash prevention side?
I deny all expertise on the subject, but it does stick in my mind that chain drives have a LOT more rattle and backlash than a good toothed belt. It's all those sleeves at the junctions - none of them are 'tight' over the pins. Maybe if you had a LOT of tension on the chain you might eliminate most of the backlash, but that would be leaning on the bearings fairly hard.

My 2c.
Cheers
Roger