IPhone – What’s the differences between the iPod Touch calendar and the iPhone calendar

If the two devices are named the same it will backup/restore the same items. My recommendation is to rename one of your devices and a new profile will be created for it.

You can set that up, but not on the device. There's no interface to more complex recursion rules in the iOS calendar app.

If you're synching with iCal on a mac, you add the event to iCal and go into the "custom" recurrence settings, and it's easy to have it repeat every two days.

Sync your device and bob's your uncle.