Blocks go under each upright so they are not sitting directly on sand.

Properly installed liners shouldn't come off, beaded of overlap.

Is the pump an above ground up-rated or in-ground full-rated? If the former, 1 hp is probably OK. If the latter, 1hp and 250# sand filter should be right, or a 3/4 hp pump with your filter.

Self-latching gates and ladders are pretty much code in most places.

yup, the K-2006 is the one

Self chlorinators are not the same as reduced chlorine systems by any means.

Carl