Quote:
He is concerned that pulling up the stair noses will also impact other wood on the stairs. Do you REALLY think this can be done without impacting wood on the stairs?
It depends on how the nosings and flooring were installed. If they are glued down and to each other, yes, it will be difficult and an entire tread may need to be replaced if the individual piece cannot be removed without damaging others. If only nailed, it will be easier. Only your installer can answer this well.
Quote:
In your respected opinion, how much impact (between the original finish) and newly sanded finish will there be? Essentially, will someone other than a trained eyed be able to see the differences?
IMO, it think it will be noticable. Furthermore, IMO, it is not very cost or time effective. To refinish an entire staircase, two 8 hour days will be required plus materials. Aluminum oxide is a difficult finish to remove.
Quote:
Pointedly, I am wondering if my installer (who is a craftsman, truly) can color, fill, repair and reseal the scratched stair noses and a few boards on the stairs with having to undetake a full sanding and/or replacement?
It depends on his skill level and experience at doing this. It can be and is done often. There are many "tricks" one can employ in repairing wood floors to disquise damage. How successful he is will depend on him, the repair person.
IMO, I would opt for replacement. You may wish to attempt to repair just the damaged boards and hold off on any settlement until you are satisfied. But I think, in the end, replacement of the damaged boards and trims are your best option.