I don't mind doing 2 MN's, especially if they are short and have meaning. One of our boy names we have picked out will have 2 MN's but there is meaning behind it. If we end up have 3 total boys I'd be tempted to do the 2 MN thing again because there are two grandfathers I would really like to honor.
Who will really know about the 2 MNs? Very few. It'll come up when she is born but otherwise I don't think its an issue. The only time I don't like it is when people get pretentious about it and say my name is "Thomas William Edward Smith" for example.
FWIW I like FN Ann Kennedy LN too. I like Kennedy, it has meaning and I've always liked the sound of it.