Well i could try that, but what happens if for example: I have 20 bitcoins, and sent 10 bitcoins to one Adress wich is unconfirmed, Then i -rescan and -zapwallettxes and now i still have 20 bitcoins, now i decide to send 15 bitcoins to another adress with very high fee.

Is it possible for that transaction to get validated even though i alredy spent 10 bitcoins though the transaction is still unconfirmed?

By the way, has the remaining 10 bitcoins alredy changed adress or will the change of adress occur when the first transaction is confirmed?