1. Ringing is configured in Flash 40. (Fl40, CO line range + HOLD) Press appropriate button for ringing and dial in the station or group, with ring mode (day, night, special, etc). I can't really add to what the manual says, as the manual for this system is really quite complete.
2. I think that there is a timeout for the backlighting on display - most likely in FL50.
3. "Toggle thru three settings on display" doesn't give us much to work with.
If the memory battery is dead, you'll be in a position of reprogramming each time the power blips - I would certainly replace if not yet completed.
Good luck!