For a non-load bearing interior wall on a 4" slab, steel studs with cement board or tin sheathing is definitely the easier route. No footing needed, still fireproof, and easier to get level and plumb.
This is pretty cool, I've been meaning to plan out some shop cabinets and always end up sketching things on paper which never works out. Might give this a try for my odd corner space situation
A simple 10-20 watt panel with a built-in charge controller from Renogy or Victron would be perfect for just maintaining the battery - dead simple to wire up and no need to overthink it.
The car audio crowd probably loves these for running thick power cables through tight spots, even if the marketing copy is a little off on typical dashboard wiring.
I'd guess you're looking at another 600-1000 pounds with all those tools loaded, but honestly I'd just throw a bathroom scale under one corner of the box and do some quick math to get an actual number before loading it up.