1- Does the iPad3 have VGA output connection to regular CRT monitor?
2- What are the output resolutions available?
3- Does it support HDMI output via cable?
4- Is it possible to use the ipad3 as a screen to display other sources? For example, connect a DSLR camera via HDMI to the iPad3 and use it as a display for the camera. Is there such an adapter in the market?
There's some discussion about that in this forum:
It's an old discussion, but I don't believe anything has changed since then. If you plan to connect your camera to a computer, this app might be of interest.
With all the questions you have, you may want to make an appointment at an Apple Store and discuss your needs with a salesperson there. That will be more efficient, most likely, than posting multiple questions in these forums and waiting for we users to reply.