Heli3, I can see you replyed but it's not showing for some reason.
The twin pilot limitation may be due to several reasons. It may be that in event of an autopilot malfunction, having an extra pair of eyes/hands is necessary to react to an excursion before it became a dangerous. This is usually for early model autopilots IFR so I think this is unlikely. Alternatively it may be that physically there's some controls necessary for Cat A that cannot be safely operated whilst flying the profile or that an extra pair of eyes are needed to monitor some flight parameters. Finally it could be that a single pilot cannot see round cockpit structure sufficiently for obstacle clearance.
In answer to your second question, yes the performance stuff is in the RFM too.