As I addressed in the other thread, you need to use a seperate model type and utilize the male, female, other to accomplish this feat. The only other way to accomplish this, without stardock adding another other, is to create these special mercenary units for people to create and then it will support turning on and off these traits by doing specifically the SupportedUnitModelType tag.
Heavenfall is correct that what you are asking is not currently possible within the current system.
The best alternative is to have the units choose 1 of a set of traits (think radio buttons), namely you can have either mercenary, or this or this, or this, but not together.
