First, when adding these 4 identical fixtures to MyDMX, you simply state the fixture via the fixture's profile, how many and the starting address and then patch it. If the addresses aren't right, you can always move them around in the DMX universe, but do this BEFORE you start programming. This is key as this software, programming follows DMX channels, NOT fixtures.
1: Yes, you can make them all do the same thing. There are ways to speed up the process, but copy/paste isn't it. You'll have to manually assign settings, or using the fader drag+shift to move like channels identical.
2: If you want to do things differently, no problem either. But it may be more work.
The FX Generator may be able to handle a good many things for you, especially with cool movement stuff. Since they all use the same profile, the FX Generator can pick up on that and enable you to be able to do lots of cool things, either same or different, depending on what idea you have in mind.
I would say it's time to play and see if MyDMX will do what you want. Download it, install it and start messing with it. You'll love the 3D Visualizer.