scruzin said..
Welcome to Seabreeze!
I would secure the steering wheel mechanically by means of the tightening the wheel nut. If the wheel nut is sufficiently tight, no additional lashing of the wheel should be necessary.
As for the autopilot, that should always be disengaged at anchor.
Depends on the autopilot. If it's a hydraulic drive it will be disengaged any way, if it's got some guts like a CPT you wont hurt it- but don't you have a wheel brake on the pedestal?