My AP is an St6001+ (actually that's the control head, the AP itself is a 400G Course Computer). Ih have multiple ST60 (some plus, some not) at twin helms (ST60 Tridata Dept/Speed and ST60 Wind at each, the ST6001 AP head to stbd and an ST60 Graphic on port, with ST60 Graphic repeaters at the nav station and forward berth.
the ST60 Multi (I had a couple before upgrading them to Graphics) will control the autopilot only in a limited way - the TRACK button can advance a waypoint or disengage the AP. In practice on our boat this has only ever happened by accident, either an errant button-push or our toddler.
The C80 is a less-networked version of the E80 I have at the helm (mine is networked with an E120 at the nav station, and a RD424HD digital radar). A good unit, though since bringing out the "wide" series, Raymarine renamed the C and E series to "Classic".
In what is IMO one of the more dubious bits of product marketing I've encountered (and this puts it up against some pretty stiff competition) they now brought out a "lowercase-e" series, which is quite different from the uppercase E eseries, whether E-wide or E-Classic). Ok, admittedly off topic but I had to get that one off my chest from a while back.
The C80 will connect to a Raymarine analog radar scanner, but I'd be very surprised if there is any inter-species compatibility between radar scanners and displays.