As a pro protograher myself, I bought this camera for casual shooting like on family vacations, aroudn the house, etc. I would rate the noise level similiar to what a Nikpon D200 was about 5 years ago... not as good as D300 but somewhere in between. Above ISO 800, moderate graininess. Hope this helps some.
I have a 16gb, 45mb/s SanDisk. The speed is what I found works best for this camera when you are shooting RAW. As to the size, I think you can safely go up to whatever your budget supports. I myself would rather have a couple cards in case one fails as compared to one huge capacity one.
I'm not sure what type of software you currently are using but I've been using Adobe Photoshop Lightroom to process, catalog and store all of my RAW images. However, there are many free RAW image processors available. I would suggest doing a google search for free RAW image processing software and try some out. Hope this helps!
Don't be obsessed over pixel counts, consider the larges print you will be making. 12 mp can easily be printed at 12 x 18 and will be not see any differences had it been a 16 or 18 mp file. The quality of the picture, tonal range, color rendering etc, is excellent on the P7700. I have gotten very good prints at 14.5 X 11 from my old 4 mp camera. One advantage of higher mp counts it the ability to crop the picture and still be able to make a large print, or corp small areas for good smaller prints. I love my P7700 and am very satisfied with 12mp pictures. FYI, I also shoot 36mp pictures from my D800 which I print up to 40 x 60. Bottom line consider you you really need, and quality pictures should be a big priority over un-needed pixel counts.
No wifi capabilities, however you can connect your camera or your SD card to your iPad with an iPad Camera Connection kit from Apple ($29). First,the Camera Connector features a USB interface. Just plug it into the dock connector port on your iPad, then attach your digital camera or iPhone using a USB cable (E17 USB Cable included with camera). Or 2, use the SD Card Reader to import photos and videos directly from your camera's SD card. Connect it to your iPad, then insert your digital camera's SD card into the slot.
Although I've never tried to use this feature in David Busch's book "Nikon Coolpix P7700" it says: "The Coolpix P7700 provides compatibility with the Eye-Fi card, ... a special type of SDHC card that includes built-in 802.11n/b/g technology. This tiny transmitter can transfer images and video clips directly to your computer or to an iPhone, iPad, or Android device using a wireless (Wi-Fi) network..."