The other potential glitch was that the player may resume playing music before the "init keypresses" are played, but that probably won't be too big of a deal for most purposes.. or will it?

Yeah but I think that some of these issues could be worked around... IIRC, when the player comes up, it does state_read() or somesuch which tells it whether the player was in pause or play status, what source was selected, etc... So the state_read() could just be fudged to whatever we want (play or pause, in tuner, aux, player...) So if you wanted it to start paused, you should be able to do so. That also takes care of having to send a bunch of buttons to select certain sources... Right?