When you said the dust cap was gone, and there was lots of play in the wheel, there is no way I would reuse the bearings even if they looked okay. Not worth messing with possible bearing fatigue (from a lot of wheel slop under load) by reusing parts when new parts are so cheap.
Also, grease compatibility. Incompatible greases will often turn each other into liquid, or into a hard clay of sorts, so just clean everything out of the hub if you're not sure what's already in there. Grease is cheap.
For example, you can often buy lithium complex, aluminum complex, calcium sulphonate, and sometimes polyurea bearing greases all in the same isle of the parts store, and some of those are completely not compatible with each other.