An AVHC and 1000 would be compatible with your system, you will have to drill two holes in your mounting plate to bolt the AVHC to, but that would be the extent of the fabrication. The Lifter station serves as a torch mount.
I would recommend Hypertherm's Machine Interface cable for the system, because it gives you the start signal, and OK to MOVE signal. Unfortunately, depending on which model 401A signal generator you have, or more particularly the software version you are running, you may not be able to use the OK to MOVE signal to it's fullest advantage. The system would be limited to the start being delay based. There are signal generator chip and software upgrades available to get your signal generator to utilize this signal.
The AVHC receives a signal from the Plasma interface box, so it would still be necessary.