The B737 NG is capable of deploying the reversers below 10' RA, although it is specifically prohibited under the Limitations section of the FCOM. I believe that was developed due to an Airbus event in which the On-Ground Sensors did not operate correctly, so they were unable to apply brake, spoilers or reverse thrust on a landing many years ago.
Cancelling spoilers may have been used as a method of disconnecting the Autobrake. It's not a recommended method, but it does work.