Good guide....one things about the group exercises is that you only need the other people at the very start of the first group exercise when it has to scan multiple people. It is not required at all afterwards and you can do them all by yourself - even the four player ones. After the exercises are done and the picture has been taken (which you don't even need anyone there to have taken), you can select "try again" and you'll have yourself a brand-new group exercise without having to go through all the menus again.
Also, there are only 50 achievements to get the 1000 and 70 achievements if you want to complete it to 1500. I've purchased both DLCs but I doubt I'll ever be able to get all of the achievements. It is brutally hard no matter how much you practice, even with the guide button glitch because for some of them, pausing the game won't help you much.
Finally...I know you qualified it by saying that a 100% completion is virtually impossible, but I seriously doubt anyone could ever complete this game with 10-12 hours of game play. It takes about 10 minutes just to do a 2-player group exercise, and even longer than that for the 3-4 player ones. Plus, considering that the Master of Themes chievo is 100% random, the group exercises (while involving no skill), will take about 2-3 hours by themselves. On top of that, the rest of the exercises, even on beginner, require lots of practice to get an A+ on. I would think that it would take a minimum of 35-50 hours for anyone to expect to complete this game, if they ever could. Unlike some kinect games there is no cheating this one (other than the guide button - but even that is tough).
I don't want to make it sound like I don't think this is a good guide because it is.
Finally, I've written some solutions on Trueachievements.com (sorry for plugging that site here) that hopefully will help some people out.