Some notes on your notes -
#4, #10 - this was a 'kit' that was released AFTER production started, not changed between Sample and Production.
#11 - The RM head was thickened not because the ball got stuck behind, but because the thinner RM head, when lowering under playfield, would catch the ball and pull the ball down into the cabinet.
Some things not in your list -
#4b - The word 'Multiball' added to the RM multiball inserts.
#15 & #16 - As well as changing the insert colors, the word 'Ready' was added to the text.
#? - The sample version of the playfield had the insert in the Menagerie for the eddy sensor. (You mention it above, but not in the list.)
As far as I'm aware, there were three main runs of playfields - the first, prototype, then the second, samples.
The 'sample' run of playfields had the 'Visit Ring 3' in the center marvel, the 'Tickle' ringmaster quote, as well as the other mentioned changes. The art differences were covered up by mylar decals - the RM head between the RM multiball inserts, and the 'Defeated all RM' center marvel.
Edit to add - both sample games I've owned had the above; the games were identical as far as the changes go. (And both had skinny RM. The post behind the target on the left of the RM that was in the fix 'kit' is needed BECAUSE of the fatter head - if you had the thin head on it, the ball could escape fine. In a home environment, I was (still am!) against installing the kit, as the number of times I lost a ball into the cabinet from the RM pulling it down was very very rare - though it DID happen..)
Of course, don't forget the backbox, too!