For posterity, I thought I'd post my findings here (so it'd be searchable for people seeking an answer in the future):

In at least a couple of missions, there is an Imperial Officer which is the figure representing a named villain.

(To remain spoiler free, suppose in a mission, an imperial officer is deployed and the rules say "The Imperial Officer is Steve. Steve gets +3 Health, and has extra abilities: ...")

I inquired with FFG on an official ruling: Is one allowed to use the "Imperial Operative" card on such a figure?

This agenda states:

"...play this card when you deploy an Imperial Officer. Apply +3 Health and +1 Speed to this figure..."

My question was: Could you apply this to a "named" Imperial Officer?

The answer:

"Yes, <Steve> is still an Imperial Officer and can be targeted by game effects as such."