I've been lurking forever... Never had anything useful to contribute until now.
Just so that everybody has an idea as to whats going on with the music clearance issues, this is an overview. I've worked in the music industry for a while.
For the CD's - You have a statutory, government right to record a "cover" of any previously released song. You just have to file for a license that can't be denied, and pay the fee of .091 per copy sold. They could record a "muppets sing the beatles" boxed set, and nobody has to ask anyone who owns any beatles songs. You just have to mail in a form and a check.
For the Video Productions - Songwriters have a right to control when their song is set to video, and the price is negotiable. You can also flat out deny it. So disney/MHC/etc. has to negotiate each track with each publishing company. The publishing companies know that Disney really wants to put out these sets, so they drag out the negotiations to get the most money possible.
There is your music law update ha