Differences between Player and Holoduke
A player actor and a Holoduke seem to share several attributes. Care must be taken while using events related to an actor APLAYER.
A player and a hologram have the same picnum, statnum, yvel, etc. This is most likely deliberate, in order to avoid an enemy being able to tell the difference.
One difference that seems to be constant is the owner. A hologram always will return a value of -1. A player will return a specific value, or a value of zero during EVENT_EGS.