1. Can I use a command to delete the file which is more than 7 days old every time it syncs? Or, alternatively, can it automatically delete older files if there are more than 6 existing in the remote directory?
This example may give you home hint:
Also your task becomes way easier once WinSCP .NET assembly is released (in about week time):
2. Can I write a command which will send a success/failed email every night so I know the status of the file sync?