Compatibility between shields
Its not just a question of the stackability of the shields and the clash of pins you also need to consider what the shields do.

Stacking the GSM shield under the LCD is going to restrict is tx/rx power unless you have an external aerial.

The LCD will require a large amount of memory and processing power, a 3.5" inch display is really going to push an Uno to the edge, you aren't going to get much time for servicing the GSM and camera.

The camera is also going to require a large amount of RAM and processing time to handle still images.  If you are processing video then I really doubt you will be able use the other shields.

You don't say if you are experienced in Embedded development.  Its different to Linux or Windows dev where resources are almost limitless.  If you don't have experience then you might find the transition quite hard.

Your question was are they compatible, I don't have the evidence but I would say no because of the resources they consume.  Sorry I can't see this project going anywhere fast. :(