May I ask you to add .json configuration in somewhere in assets/emi_loot? Or maybe it's possible to do already, I don't know.

If not, maybe some .json in assets folder similar to this:

{
 [
  "gameplay/fishing/fish",
  "gameplay/fishing/treasure"
 ]
}

(undocumented recipes will move at the bottom of the list)

And then "treasure" loottable will be below fish loottable

I believe this is a possible future feature for EMI itself. I don't plan on special support just for EL categories. Otherwise, this is still better as a feature request for base EMI.