Re: the Water heater photo:
I wouldn't be concerned about the plumbing-clean solder joints w/no flux residue, Smitty pan w/drain (for the future leak in the tank), steel angle strut to spanner on ceiling to support the 50 lbs. or so of water.
My concerns are - disc. for DWH not accessible, and MC cable in contact with the copper water piping where it runs through the wall.