PDF header inconstistency across pages

It appears that you don't have any header rows. Were they taken out in the transform process or do they not exist? I would first select only the tables, and get rid of the pages. Then you should be able to promote the headers. Then you can choose the column names that you want to keep. Having the table with the greatest number of columns in the first row means that none of the subsequent tables' column names will be missing. After that, try to filter out any tables that you don't need--you know how sometimes on PDFs there will be some random three column table that you don't want as part of your dataset. Assuming the data you need is in table format in the PDFs, you should be able to filter to just the tables you need. Sometimes it's a pattern like every third table--you'll figure that part out. My point is that you need to get some headers in those tables before you expand them.

If there are missing fields when you reorder, the MissingFields.Ignore parameter handles that.

These are the steps I always take when combining PDFs.

--Nate