4 stereo channels when in VC mode

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Hello
I want to buy an audiocard Audiophile 2496 to start to use in Nuendo four separate stereo Virus channels at the same time. It has 2 pairs of analog and an s/PDIF digital stereo input.
Before I do I need to make sure that what I expect from the card in connection with the Virus will be feasible. I assume what follows is correct; if I'm wrong please tell me.

In recent posts at ampfea I read it is possible in USB mode to use both the USB outs and the physical analog outputs. In total it gives five stereo outputs at the same time. Now, the manual says four. What happens if you assign parts to all of them, that is USB 1&2, analog 1,2&3 (all stereo) - will one of them simply not play?

Those analog outs have to be plugged into the card and configured as inputs in Nuendo (external instrument function, I guess). Right?

Due to limitations of Audiophile 2496 (two and not three stereo pairs of ins) it will be possible to use two USB audio channels and two in Nuendo project - four stereo channels in total. Right?

What about the syncronization between the USB and analog channels?
I know there is latency compensation parameter for external instruments, but I mean the rhythmic stability, f.e. once the compensation is set correctly, no desync problems of USB and analog notes appear, etc.

Does anybody use such configuration without problems?
Can the recent Nuendo handle that well?
Is there a workaround for this trick in Cubase which does not have this option? (asking because on a different platform I might need to use Cubase instead).

Hope you can help.

Thanks

T