Well,
Just a thought here. Seeing as this is a Mirror Mirror campaign, we don't the members of the Terran Empire adopt the names of the players who are representing Starfleet.
How it would work is those of us in Starfleet use the prefix UFP and those in Terran Empire use the prefix TE.
The simplest and easiest way for the players on the TE to play as an alter ego would be to put the name of the UFP players in a hat and have the RM draw a name and that person would represent the other side.
Then here's the example:
1. Chutt would go be the name UFP Chutt in the campaign.
2. Chutt's name is drawn by the TE RM and assigned to Green and he would become Chutt's alter identity for the Terran Empire and go by the name TE Chutt.
If it's going to be mirror, mirror then lets make it as entertaining as possible.
And Dh for your quote:
"
Woulkd the Mirror DH be a moral, church-going kubaya singing hippie?"
Here is TE DieHard's theme music
Oh, the assignments should be kept confidential by the TE until after the campaign is ended. That way we can all have a laugh.