When switching between recording start and stop with the remote control input terminals (option /R1), can I disable recording start/stop witih front panel keys?

Yes, if the option includes header printout (/BT1). In the remote (Basic setting mode) settings, select Remote key lock priority.
For details, see section 7.18, "Assigning functions to the remote control input terminals (suffix code /R1)" in the user's manual.
If you don't have the /BT1 option, use the key lock.