Just speaking from my own experience, I've had the best luck by importing .dbf files into Arc.  Always had issues with Excel, I believe that was an "undocumented feature" in ArcGIS.  CSV files can be quirky, too, and I prefer to avoid them.  Why?  Because your data may have values with commas (such as "City, State"), which will cause problems with a csv. 

My best advice would be to work with the people creating the tabular data and establish standards for your data values and formats.  Otherwise your data will contain a dozen ways of saying the same value.   

Sorry, I've never used FileMaker.

BB