I typically enjoy a couple while brewing. I did however impose a time frame of no drinking until the boil for my brother. Seems he would not really clean things before putting them away, only for me to find the next time we brewed. :cross:
Probably, you'll need to pressurize them with gas first to see if the seals are good. They will leak with no interior pressure forcing the gasket on the lid to the top of the keg.
As far as state goes, Foggy Noggin over in Bothell brews out of a detached garage at his residence. 192 brewing in Kenmore used to brew out of his 192 square foot shed, but he moved. Not sure on local zoning. I think that is where your issue would be.
Just get some thin backerboard (the concrete stuff for tile work) screw that on then lay your stainless over that. Your current set-up may be fine, but why risk it. :mug: