Romney may be a spineless poll-driven politician, but I don't think he's a total idiot. I think he is is smart enough to realize that there is a difference between being in the Oval Office and on the campaign trail. I think is intelligent to know that once started and the drag of continued combat happens, the public loses its appetite for the war it thought would be a quick and easy contest. So I don't expect he would start a war with any of the listed options, as none of them would be quick and easy, tho he would back Israel to the hilt if a fight with Iran broke out.
If he goes and invades some place, I expect he'll go for his own version of Grenada. A small country that he could reasonably present as in need of American intervention to restore freedom and which the U.S. could overwhelm with ease. The Maldives and Fiji come to mind as possibilities.
So a moderate hero invasion? How about Transnistria? They have a terrible Freedom House score and aren't recognized by anyone.