I cleaned up my earlier ‘fix’ a bit. The first attempt used a dataset.onReady() to run a repeater.forEachItem() that show()'s each repeater item’s button. The idea being that at the very least the dataset was Ready before the button was ever visible and clickable. I still don’t know if dataset Ready also means the data is finished connecting up in the repeater, or just that it is ready to start connecting to items in the repeater.
I changed the dataset.onReady() set the onClick() callback on the repeater template. This way, the onClick()'s for the repeater buttons aren’t ever defined until the dataset is ready.
(Previously I had the onClick() set in the page code as a function and connected it in the Editor Properties, so onClick() was defined earlier. )
Anyway, I’m going to try to use a set of console.log() calls to see if I can determine in what order everything is loading and is ready. If I learn anything, I’ll let you know!