There is a ton of pattern matching that the 5e rule set does for NPC that automagically populates effects, but if an NPC does not match the predefined patterns, nothing gets generated.
I ran into that for a conversion I just did and I made an effect and explained how to use it as a conversion note.
I also have that module, and I have been doing a freelance job recently doing monster conversions so a lot of the standard wordings are fresh in my memory, I'll take a quick look and see if there is an obvious match.
Unfortunately, the ruleset does not allow you to cheat and prebuild effects and auto attach to NPC.