...does it not simply indicate that the galaxies WERE receding faster IN THE PAST?
Essentially, yes. What you would have is essentially the following data:
Careful. The expansion of the universe has been accelerating for the past few billion years, so there is a range of redshifts where the galaxies were receding slower when the light we see was emitted than they are now. The linear Hubble law only holds for small redshifts (i.e., much less than 1).Essentially, yes.
The observable universe grows faster than the scale factor, as light gets more time to reach us - we see more distant objects than we could see 5 billion years ago. "Size of the region that is today's observable universe" works.(If the word "size" bothers you because our best current model has the universe being spatially infinite, substitute "observable universe" for "universe".)
Yes, but due to the way the universe has been expanding, many galaxies are receding even faster today than they were when the light we see left them.