What is the axle spacing?
If the axle is long enough there's no reason why you can't just install a freewheel re-space the axle and dish the wheel accordingly to match.

A lot depends on what type of bike you wanted to use these on. Right now their set up as a flip flop rear, but the presence of ta hollow axle tells me its not likely a track bike wheelset but just a set of wheels someone built up or ordered to convert their current bike to single speed. Measure the overall axle length, and measure the overall lock nut to lock nut distance. Skewers are no big deal, chances are you can use either your old skewers or source a set elsewhere.
If the wheel is dished evenly left and right, and the spokes are proper length, there's no reason why it won't handle being redished for a freewheel. The difference in the average wheel side to side is on millimeter or less in spoke length. The majority of factory built wheels for years used one spoke length front and rear and they worked fine.