About the mouse sync, how are the window alignments? Let's say you run them both in window mode with one WoW window on each screen. On screen 1 you got wow in windowmode, covering the whole screen except the task bar in the bottom. On screen 2 you have it window mode over the whole screen, with no taskbar. If this is correct the sizes of your WoW-windows are the not the same. Wow window 1 are a few pixel's "shorter" making the cursor a little bit higher then the other screen.

This will easily be fixed by making both windows window-mode but also checkign the maximized box.

If im completely off the track please tell me, but it's hard to help you with that unless you post a screenshot or something.