Yep Keep Options in CS5.5 do not work.
I believe it was addressed in subsequent versions. Download a trial of Adobe InDesign CC2014 and check.
I don't believe this has been addressed. I am having a very similar issues. I have five columns. 4 lines of type. first 2 set to span 2 columns. last 2 set to span 3 columns. The last 2 will only float up if it is set to 2 columns or less.