I think it's great what you are trying to do for your daughter so I hope this helps. While MC is hands down the best file management media player I have heard of or seen, as you know, it won't help with this. So, two good choices are Windows Media Player 9 or 10 and Winamp 5.x. Winamp is the better of the two for Karaokee as it links directly to karaokee sights for downloading the karaokee version of songs you already own as well as plays the files themselves. It also features a plugin called "Evil Lyrics", which when installed and operating with Winamp as you play your own mp3's, WMA's and such, will actually go out and retrieve the lyrics for the song you are playing and post it to your screen. I have found it to be about 90% accurate. You can save the lyrics or copy and paste them to the songs themselves. When the lyrics are incorrect or missing, you can always correct or add songs that you know the lyrics to and upload them to their server for the commuinity. There is also a software program out there that I am currently testing that takes most of the vocals out of most mp3's, wma's.... so that you can make your own Karaokee like songs. I hope this helps.
Mark
PS. Did you source those files from someplace I can get them?