Can I move these around the shop or are they fixed?

These are standalone tables — you can position them anywhere you need workspace. Stack them to save floor space when not in use, or spread them out for multiple work zones.

Will polyurethane hold up to gasket scraper, wire brush, and impact tool work?

Polyurethane is dense and resists gouging under normal shop use. Heavy repeated impact or sharp scraping will mark the surface over time, but it won't degrade or absorb solvents the way cheaper materials do.

Do these tables come with any fasteners or feet?

The tables ship as complete units. Check the base before first use — if feet or leveling pads are loose, tighten them down to keep everything stable on uneven floors.