OK OK I want to take the test also

#1--Looser piston fit is needed because the cylinder jacket is cooled by water reducing it's expansion. Our plane engines run hotter and have closer expansion rates between cylinder and piston??
#2--Pistons don't break-in or should not be made too.
#3--Refer to #2
#4--In a perfect world only the ring would touch, but the skirt is usually main contact point.
#5--A few tanks of fuels will break in the ring. Rings are softer than any chrome or Nikasil coated cylinder we use. Otherwise we would never need to replace the ring by itself as we frequently do. Nikasil is honed with a diamond hone.
#6--Rings, but bearing loosen over time too even though I would call that wear because they do not need breaking in.
#7--Rings benefit most from breaking in. In the old days of big block engines (cars) as soon as we got it running we would do at least 10 full stop full throttle accelerations to help seat those huge rings in those massive bores.