When choosing shields you should make sure they will fit height-wise with each other. You can't have some big component that is several cm high sandwiched under another shield, the pins won't reach. Second is to see if any analog och digital pins conflicts. The datasheet for the shield say which are used. You can also try this sight (search for "xbee" in one search and "motor shield" in another) and see if you can find the same shield.http://shieldlist.org/
The wireless IP camera. Is it really wireless? A lot of products that are "wireless" of course have a power cord. Wireless here only means it doesn't have a cord for data communication (i.e. network cable).
But if it runs on batteries and the motors and motor shield can handle the current needed to drive this I think it is possible.