You can disable display output, mouse and keyboard input, audio, remote USB, or clipboard individually in the VRDP server.

The following commands change the corresponding server settings:

$ VBoxManage modifyvm VM-name --vrde-property Client/DisableDisplay=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableInput=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableUSB=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableAudio=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableClipboard=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableUpstreamAudio=1

To reenable a feature, use a similar command without the trailing 1. For example:

$ VBoxManage modifyvm VM-name --vrde-property Client/DisableDisplay=