You can get a separate camera app with a silent shutter, such as the ones linked in my sources. The reason your shutter and camcorder still make a sound is that in some places it is now illegal to have a silent camera, because of voyeurism and illegal photography, etc.
What I do, personally, is...
Absolutely! The Galaxy series of devices are some of the best Android devices in their classes on the market! You can certainly get cheaper tablets (as cheap as $80 on some online stores), but as far as speed and quality go the Note is hard to beat.
No, i900 and R760 cases will not fit the other phone. Those phones are not even even slightly related. Unless you mean the i9000 (three zeros). They have the same dimensions, but their camera lenses are different, so if you get a hard case, it probably won't work. If you get a soft gel...
Johnny Depp, easily. Tom Cruise is a GREAT actor, no denying that, but Johnny Depp can really seem to immerse himself in a character in a way that Tom Cruise doesn't do.
That device is known to have hardware issues, sometimes fatal. Unfortunately it may just be time to upgrade, or get another one of the same device on eBay or something. At this point your phone is a five-year-old model, so you could probably find the same one for under $10 online.