Don't know the specific model numbers of autopilot you speak of but I flew various different models of the B727 from the -100 through the -200 series.
We had a very basic autopilot on our original aircraft, certainly had no altitude capture, that was done manually then Alt Hold was selected. That AP basically could just hold pitch and heading.
We acquired some more advanced -200's in a merger and these aircraft had IAS hold and Altitude capture as well as VS hold.
As far as how it performed in the scenarios you mention, I don't remember too many failures, the AP was pretty basic but it worked well.
You certainly wouldn't be using it on the later stages of an engine out approach though, it was no triple 7 !