1. You might want to backup your contacts, tasks, appointments, and messages (i suggest pimbackup)
2. No. and please dont. they don't need to know about our leaked ROM.....
3.It will work if done correctly.
4. You will need to unlock with cokeman's newest unlocker-2.31. this thread will help you
http://forum.ppcgeeks.com/showthread.php?t=17473
5. also covered in link above.
beware-no one will take responsibility IF your phone is bricked.... please read more than you deem adequate, as upgrading can brick your phone. other than that-flash away!