This is good news since the solid state (Nakamichi IA-1z) integrated apparently has an onboard DAC (I could alway refer to the Nak's manual) since I am currently running a digital coax from the Apollo's digital out and it is definitly working and sounds great.
If this is the case, it is simple enough to test it. Simply connect a pair of RCA interconnects from the analog outputs of the Apollo and into an open RCA input on the integrated amp. Switch back and forth between the analog connection and the digital connection while playing a CD. If it works, you know both outputs are active at the same time (I've never know a CD player that didn't have both active at the same time, but I haven't owned ever CD player in existence).
If the test proves that both are active, there won't be any issue with having the player connected to two systems. I've done it many times with many different CD/DVD players and amplifiers/receiver.
I guess it is possible that it could create a ground loop hum. If you do happen to cause a ground loop hum, look here in the archives for solutions.
Enjoy,
TIC