the o.G. and m.G. make me think 'ohne' and 'mit,' with or without, but nothing's coming to mind for the 'G'.
Anwärter was a cadet, or candidate. I'm not entirely sure if it meant under-going training, or waiting for the check to clear for Party dues.
Going from Mann to Sturmmann was indeed a promotion, but I don't know what the pay rates were at all. I don't know if that figure was his raise, or his new pay.
Feldgrau für alle und alle für Feldgrau!