Lomapaseo:
I know you are a bit of a flight safety boffin from previous encounters on Pprune.
You are now asking me detailed questions about an accident that took place about 33 years ago but I will do my best to answer.
The DC-10 had 3 hydraulic systems - all of which fed the flight controls in one way or another. As already stated, there was no manual reversion (like they had on the B707). Therefore, no hydraulics, no control (except that it was just possible to fly using differential engine thrust).
I have in front of me two hydraulic diagrams from my original AA DC-10 manual.
The leading edge devices (slats) were controlled by No.1 and No.3 hydraulic system.
So, the loss of No.1 engine (and its pylon) when it went over the top of the left wing not only retracted the slats on the left wing but wrecked the No.1 and No.3 hydraulic systems.
That leaves us with the No.2 hydraulic system (and I make a huge assumption that it was entirely intact).
The No.2 system (and I am only talking about flight controls here) controlled:
1. Half of the outboard ailerons.
2. No.5 spoiler on each wing.
3. Inboard half of each inboard and outboard flap section.
4. Spoiler No.1 on each inboard section.
5. Half of each inboard aileron and flap section.
6. Roughly speaking, one third of the elevator (the horizontal stabiliser - which had the same wing span as a DC-3 was controlled by No.1 and No.3 systems. So even if they had survived all the other bits, landing would have been a little bit "tricky" - as we Brits tend to say).
7. The lower rudder.
If you are still with me, the rudder was in four pieces. It was protected by non-reversible motor pumps which ensured that a reservoir of hydraulic fluid would always be available for the rudder.
The rest of the flying controls had motor pumps fitted. In other words, as long as you had hydraulic pressure in one system, then the motor pumps would power the other system as long as there was no leak in either system.
I cannot promise that I can answer your next question but I will certainly try.