On the first point, I would set up the Filemaker file to export the data as a merge file, with a constant file name, to a constant location. Then set up the Excel sheet under 'Data -> 'Get External data -> from text file' to import the fresh data from that exported file. You will only have to set up the formats, calculations, etc once.
You can script the export from Filemaker.
You can script that Filemaker opens the Excel sheet.
You can set the Excel sheet to import by a macro, or to 'Update data sources' upon opening.
Hence, you click a button in Filemaker and presto the next thing you see is an Excel sheet with all your new data fully updated.
On the second point I would have a script do exactly the same thing, except go over to the table that holds the portal's records, 'Show only related records', and export from there. You will then have one record per row in the Excel sheet.