Kretan BodyGuard

[Mediolanicus]

Unless you spawn the general by script you can only change the bodyguards for all FM's.
Having multiple bodyguards for 1 faction is impossible (the starting Spartans for the KH are placed at the beginning of the game, only that is possible).

Changing the unit for the recruited generals in a certain region is possible, though not for those you've already recruited.

[Ghaust the Moor]

Well, What I have done is given Kydonia to me from the start, and I gave myself a Kretan general. I was going to change his bodyguard. I have yet to start the game.