[@Jedly] As a rookie with no kills, you wouldn't have a callsign- callsigns aren't something you pick, its something your squadmate's pick out for you. Anyway, while a rookie wouldn't be out of place- I am a little hesitant on that because we already have a 'rookie' character, so I'm not sure how well a second one would throw into that mix. Likewise, he wouldn't get to 'pick' which machine he piloted, he'd be assigned to something he'd qualified in during training, like a sparrow or sentry, and then upgrade to something the squadron has, typically something mass produced as opposed to a custom - especially a one(technically two) of a kind machine.

Speaking of Zeitgeist, what do you mean Erwin requested it to be commissioned? These machines cost in the millions, where does one get the money to request a specific machine? and if it were the military that Erwin requested from, why would they listen to one of their hundreds of rookies and purchase them a high performance/high cost unit? A machine like that is just not something one would give to a rookie.

As far as the actual Zeitgeist itself goes, everything makes sense, the SMG needs a caliber sizing/ammunition count, because while I won't be forcing you to keep track of every shell expended, if battles become long and drawn out, and your character is very liberal with his trigger finger, it is possible that he runs out of ammo.