Actually the puppets were fixed up to play the munchkins in The Muppets' Wizard of Oz...which is also where the gas mask Rizzo wears in the one opening came from.
No, Brian has not walked away from the Muppets, although he is very busy with running the Henson Co. and whatnot. However I think this recast (similar to Brian passing the Scooter and Janice recasts off to others) may been mainly because Brain was not a real strong Newsman replacement in the first place and not comfortable/interested in continuing. He took him on for "The Muppet Show Live" but I don't know if that was ment to be a permanent replacement or just the best or most convenient they could get at the time. I personally think Steve is great as the Newsman and I hope we see more of him in the future.
From the main page scroll the navigation wheel in the upper-left, click on the gadgets icon and then open the News Flash Ticker. This will launch in the window...or you can add the gadget to your DxD profile.
The music clips are intended to be just that, audio clips. Users can add the songs to their DxD profiles and you can listen to sample from the various Muppet CDs... there are no plans to add video or other visuals to music clips in the music section... however some musical video clips may be added to the video sections in the future.