Here are the answers you seek:

You are correct in your assumption on quality. Not only is this true with Revisited, but extra true, in that the DVD9 is the final draft with bonus features, the DVD5 is missing one or two things and has no bonus features, and the Xvid has several changes that weren't done or even changed again.

I believe that all DVDs are the same resolution, its the compression on them. The DVD5 has little compression, the DVD9 I think matches quality-wise with the official DVD.

While the Blu-ray is coming out, the 1080p videos are already available from broadcasts in Europe, but they came too late for ANHR to be done in HD. Ady has stated in the past that he is not interested in Revisiting Revisited and that many changes could only be done in SD. This is not the case with ESBR, which will be 720p since his computer could only handle that much, and the rest of the saga are already slated to be done in full 1080p as he has a new computer.