Will we ever see UEE uniforms in the PU? Particularly for Players who want to RP as mustered-out soldiers, former Admirals, things like that.

There's no official plan, but if they do it, it'll be after Squadron 42 is released. There are further questions related to this that would need to be answered, such as: What ranks would people be? (because that's something that's fleshed out for Squadron atm) What would the UEE be in Star Citizen exactly? (A Peacekeeping force? A Guild? A Faction? A Group?) It's something they'll talk about [internally] once Squadron's been released.