It is my understanding that the signals will be output from Blu-Ray and HD players via HDMI 1.3 only. I could be mistaken, but since the Panasonic is only 1.1 compatible, it would then become very relevant.
Yes. It will all be done by HDMI 1.3, which is entirely backward compatible and through which your projector will communicate with the player telling it, in effect, that it can only accept a signal of up to 1080i. Most likely, however, you will be able to set your player to send the best signal...