I managed to work out the animation, and got the collective lever working.

For info, if you're using the Graph Editor in Layout, then you need to set the curve to Linear, and not TCB or else it looks for extra parameters, and I don't know what they should be. Linear seems simplest. Each key frame can have its own curve option. So although the wiki says TCB is allowed, I couldn't figure how it works.

On the plus side, I might now be able to figure out how to animate the door opening and closing.