I had something like that happen, I had to turn the phone off, remove the battery, re-insert battery, restart and select the Sprint Scene, and the widgets (4G, GPS etc) returned.
That depends on what device you are using to put the music files on your sd card, and what media player you use.
I had a hard time getting the properties on some of my albums, so I went into Windows Media Player, I have a machine running Win7, updated my music info, then went into windows explorer and just drag-and-dropped. All the informatoin should be there after you update the artist/album information.
I just for now want to use the default player, but maybe it doesn't have the capability. Wait, it does, just checked. Yeah still unsure how to do this.