I’m not really what the problem is you’re describing. Could you explain on this please, maybe share your code too
“Where I’m stuck is updating the options for a different select element–I cannot seem to hit on the right function to update/replace the options in the taxonomy/term dropdowns (on the block–the widget does it just fine, but the block requires a different approach).”
As a general note, you probably should be using the new Data models and not making your own api calls as they won’t be as integrated.
Hope can help if you don’t mind explaining a little more the problem.