Also, when in game FreeOrion takes complete control over the cursor and I have to CMD/Alt-TAB on the keyboard to change windows and get it back. Is this normal? It's not all that much of a concern, I was just wondering if it's a bug or not. I also use Boxer (DOSBox) and in that you can toggle whether the cursor is locked to the app window or not.
This is a property of the Ogre input system that's currently being used, and which is not very good. In windows, you can edit OISInput.cfg in the main freeorion directory so say w32_mouse=DISCL_NONEXCLUSIVE instead of DISCL_EXCLUSIVE but that most likely won't work on OSX. There might be an equivalent, or the X11 entries might affect OSX, but it's not obvious from the file and I don't have any way to test.
You can change the resolution in options or by manually editing the config.xml.
There are also resolution controls in the options video tab. These "should" work, but can be buggy as well, depending on the OS.