Regarding Galaxy dump / CSV files from IDE

Hi everyone, I am wondering about the export/import of galaxy dump csv files.  I recently realized that you don't need to include every column when importing them.  I am however not sure what rules apply.  Is it enough to have tagname + other columns of choice or are there mandatory columns that have to be there?

Also would it be possible to do a batch rename of multiple tagnames  with a csv import?

regards

Jakob