Yeah, the doors are opened for listening. The wife and carpenter both wanted to install permanent mesh in front of the speakers, but that would've been one too many things to kill the sound quality.
1) I was aware of these hinges, but the carpenter didn't like the visible gap that has to be left in order to let the doors slide in. Once the wife heard that, it was basically me vs. them, and majority rules.
2) There is a fair amount of height for slidable platforms, so that's still a possibility. Will see what kind of effort that will require.
3) Oh yeah, there's room for the VP150 in there. For reference, the entire cabinet is 14-feet across, and the TV cutout alone is 5 feet wide
And I double checked on the optical cable. The TV does have an optical audio out (i.e. to listen to OTA HD programming in 5.1 audio). So, I'm safe there.