I propose to add a new function to be added in EEF.

A simple function to check if a monster is disabled in most events like a random monster encounter in Souting II events.
The default monsters to be disabled are those that should never appear in the hero army slots plus emissaries.
The function result can be modified by mod makers. They can define their disabled monsters, usually some boss creatures that should not appear elsewhere.
This function can help build mod compatibilities. For example, to disable a new monster added by typhon to appear in all those WoG Scripts events, we only need to change the result here, and then it applies everywhere.