How can I disable the Option+click hiding behaviour?
One option would be to remap Option+Left Click to something else using KeyRemap4MacBook.  It might not have exactly what you want, but I think it's not hard to add new shortcuts (or ask the author to add them for you).  One option that I saw was Option+Left Click -> Middle Click.  You could then (assumedly) set middle click to do what you want in Zoom2, and retain the Option+Click shortcut.  

Of course, if you do this, it will change Option+Click everywhere, even if you aren't clicking on another window.