Hello, Greg.
Resolution: You can always right click a layer, go to Properties>>Source. 3rd entry is the Cell Size. (1/9th arc second data is approx. 3 meters)
See where the points were collected: No. The NED is an interpolation result. You would need the original dataset to see actual collection locations.
ArcGrid vs GridFloat: ArcGrid is an integer grid, whereas GridFloat is a floating point grid. Basically no decimal places vs decimal places.(float also can store a larger number).
Regards,
Jim