Disklavier

My DC5A got delivered Saturday afternoon and I'm having a blast with it.
My wife (despite some complaints of the size of the thing) has come to
love it, she's going to wear out that Carol King Tapestry Smart disk
set   I in anticipation.  She already had the thing fired up playing
the Crendence set even before I got down for breakfast this morning.

I've not had too much time to play with the various ins and outs by
experimentation yet, but I'm off to get some cables that are the
appropriate length (my wife refuses to let me leave the untidy like my
old synth rigs were).  I've got my computer and it's associated ADAT
stuff in a little wheeled rack under the comptuer.

So here are the questions:

1.  Getting the piano to play the MIDI out of the computer was
straight forward.   However I didn't see any midi traffic on the
computer inputs when I played the keys on the piano.  Is there some
not immediately obvious setup I need to do to the piano?

2.  What exactly appears on the AUX output of the amp box.  Is it the
same as the speakers?

3.  What about the AUX input of the amp box.  The big question  here
is does it mix in to the TG audio to the headphone jack on front of
the piano?  It would be much neater to not have to have a seperate
headphone amp.

4.  What about the CD Audio/MIDI ins on the the control unit?