Answers for B767. They would be typical for other types though...
1. No, not usually. Lateral control by limited spoilers, Pitch by stabiliser trim.
2. Accumulator.
3. No flaps, no reversers
4. As per 1. Flight Spoilers, and not all of them. Only those from the hydraulic system that is powered by the RAT. In the case of a B767 for example - the centre system.
5. A Hydraulic Motor Generator provides emergency ac power - basically the standby instruments and VHF1. With the HMG running you won't deplete the batteries.
6. B767/B757 have two batteries. One is for the dc power system the other is for APU starting. There is a customer option available that allows for coupling the two together in emergency. The theory is that you get more chance of starting the APU. You wouldn't even try if you'd run out of fuel one hopes...
... because the reality is that in the extremely unlikely event of the APU failing to start, you have consumed available battery life. If you try but fail to get the APU going, don't bet on them lasting for 30 minutes, let alone 60.
Maybe you worry too much!
