Well...

Kol: Very experienced admiral.  He knows what he is doing.  Probably would have wrinkles, a and a short beard with a bit of grey in it.  Perhaps give him a bit of an exhausted but attentively wise look to show his weariness of battle, but expertise at it.  Basically, the iconic TEC guy.

Akkan: Some guy in a uniform that is very neatly pressed and looks to be middle-aged.

Dunov: May look a little nerdy and may be working with a computer or something...

Sova: Young commander that looks fresh and has likely never been in control of a capital before.

Marza: Semi-short, semi-fat guy exuding a very funky smell that likes watching things go boom a little too much.

Kodiak: Perhaps a younger version of the Kol guy, but less weary of battle and seeming to have more vitality.

Hoho: Mad Scientist.  Since this is sci-fi, why stop there?  Why not just go full out cyborg?  You know, half his head is glowing and you can see little circuits and whatnot inside his skull.  Perhaps have a prosthetic arm/leg or two...  You get the idea.  Oh, and his voicebox has to be prosthetic (given the way he talks)

Cobalt: A young, very fresh recruit standing at attention.

LRM: A slightly older more experienced officer with hands behind his back.

Well, there you go...  My two cents...

Although ROFL @Rezo/Darvin

Volt, except for the Marza (which is in the OP), your descriptions are so close to what I had in mind for those guys, it's scary...

You know, while the Advent frigates have a good range of voices, all of their capital ships sound like young girls, though with somewhat different personalities (most pronounced are the Progen and the Revelation, which are on the two extremes of calm and excited scale).

And so, with that in mind:

That is kinda scary, but pretty accurate...  Well, Darvin, there you go...