The template really only inserts the block type, not anything specific
like the source language or export backend.
Right, but based on the code you have, you can easily add "SRC org", "SRC emacs-lisp" to the default value of that list. Looking at that, users can also get an idea that they can add their favorite languages to that list too.
I think prompting for
"second-level" information like that might be a little overkill.
I second that. The first-level prompt also feels a bit slow, honestly, compared to using easy templates like "<e". So in my config, I make "<e" (just an example) to insert the, well, EXAMPLE block as usual. But *if region is selected*, it does the wrapping as in your code.
This is what I mean (GIF animation):
I use hydra to provide those awesome hints.. but the same can be done without hydras too.
As for what should be escaped and what shouldn't, I defer to Nicolas,
let's see what he says.