Is it acceptable to use other descriptions for driveway entrance plaques (NYW5-16P, NYW5-17) than the “Hospital” and “Fire House” mentioned in the NYS Supplement?

Yes, the illustrations are just examples and do not represent your only options.  You want to be careful, though, to use descriptions that are actually helpful to a motorist.  “Fire House,” for example, lets a motorist know that the driveway is used by emergency vehicles, and is likely not active (hopefully) most of the day.  “Hospital” suggests that the driveway is likely used throughout the day, and might carry emergency vehicles.

The NYW5-16P is used when there is only a need for a single line such as “Hospital”, “Park”, Trucks” or some other description that would help motorists The NYW5-17 plaque is used for 2-word descriptions such as “Fire House.”

References

Manual on Uniform Traffic Control Devices (MUTCD)
NYSDOT

August 2015