I have had a 1920 Duo-Art Steinway, 6'1" in length, for almost 20 years.
The player mechanism had been removed before I purchased it.  I have
always dreamed of making the piano 'complete' again.  Recently I found
at eBay a "complete Duo-Art player system from a 1926 Steinway Model
M XR ... You will receive everything to make your Steinway Grand Piano
back to its original condition."  https://www.ebay.com/itm/113175097611 

I love mechanical music, but I know nothing about installing or repairing 
or how any of it actually works.  Nor do I have a desire to learn how
at this stage in my life!  My questions are many:

1. Will the 1926 Duo-Art parts fit a 1920 Steinway piano?

2. How much should I expect to pay somebody to install these parts to
make them work beautifully?

3. With the player mechanism installed, is there any repair work that
cannot be easily done to the piano?

4. If my piano needs work in general (maybe even replacing pin block!),
should I do this first?

5. Does the mechanism effect the piano action at all?

6. Do the parts in the eBay link actually look like everything I need?

I am located in Easton, Pennsylvania (USA), about an hour away from
both New York City and Philadelphia.

Thanks so much!

Tom DiGiovanni