the circlips are what keeps the wrist pin in place in the piston.
not sure what you mean by loose cylinder. figuratively speaking
i think you would know if your cylinders were loose. lol
the cross hatching is the pattern that the hone makes in the cylinder wall.
if you have a good many hour on your engine, chances are your rings are
worn out and yes, you will not have as much compression.
also, you can run your fingernail along the top of the bore to see if it
catches on the edge. where the piston ring stops near the top of the cylinder
it will leave a "ridge". of course the best way to tell cylinder wear would be
with a bore gauge.