Can you help with any of these questions?

Personally, I hear no difference between MP3 and WMA so I always stick with MP3 since it is a universal format and works on just about anything. Plus if you have no other Digital Rights Managed files you can keep the Fuze in MSC mode making it possible to drag/drop files to it from your computer rather than using Windows Media Player, Rhapsody, etc. I also rip at 320K bit rate, and use the Constant Bit Rate mode rather than Variable Bit Rate. The Fuze doesn’t seem to like VBR files too well. 

If you don’t mind having two copies of everything, you can use a FLAC program to rip your CD’s to the PC for perfect digital copies, then convert these to MP3 for the Fuze. 

Since the headphone jack on the Fuze is not a true “line out”, you will have some compatibility problems when plugging into a line in or aux input on a car stereo, etc. Play with the volume control on the Fuze to get the cleanest sound, but be warned that the sound level won’t be the same as a CD at the same volume setting, thus it may never be as loud. Also, switching from playing the Fuze to a CD may result in a sudden increase in volume that could damage your speakers, and your ears. Always turn the volume of the stereo down before switching inputs. If you are so inclined, there is a way to build a cable that plugs into the PC interface of the Fuze that supposedly gives you a true line output for which you can find the plans somewhere on this forum. I don’t know if it’s worth the effort, however.