I would go for recovery menu right away
That is the Rebug CFW, Rebug sounds as debug and that is what it is, a CFW with many debug options
For playing a backup any BD game disk can be used. So you can leave that one disk in the drive and play any game (with max FW 3.55, unless you have a True Blue dongle aka TB Dildo)
Don't know about the cinivia files. Latest BD movies and latest games (FW 3.55+) don't work.
Nope, only if you have a very early PS3. Other option is a Cobra dongle but PS2 emu isn't that great because only the real Emotion Engine chip can do it.
Don't know but I don't think so. Better rip it to a mkv file or something. No irritating advertisings also that way