#1- who knows
#2- Yes - seidio dot com for one. Lots of other places sell em too.
#3- No - The pearl doesn't send mp3 info over the bluetooth. Mine doesn't at least.
#4- I'm sure with the headphone jack converter any fm transmitter would work.
If you do a little searching you can find all the links for new headphones, or the converter you're asking about. I've gotten the answer to all of your questions just by reading all of the smart people's comments here on BBF.