iam in germany and as far as banks go sparky is pretty s##t most blokes enlist the help of german girl freinds and such to do the talking, most of the time you get the old ( the unit before you messed things up not paying bill etc ) see 'tarred with the same brush'
Shouldn't be a problem. If you have your self service password once you've set up the account (which won't take long from what my sources tell me) you just add it yourself and decide what goes where.. or your HR staff can do it if you don't have self service
It doesn't matter wich bank you use in Germany, you will be able to get a Dispolimit (overdraft) with all of them.
You can normally have two times that of what you put in the bank each month, so if you put 1500 Eur in each month you'll get a dispo of 3000 Eur.
It also doesn't matter if you are overdrawn each month so long as you do not go over this limit.
You will ofcourse pay some intrest on this.
If you don't have much money I would recomend another bank like Post bank for example it's cheaper so long as you deposit a min of 1500 Eur each month.