@Christine,
Have you tried making a form which DOES have a drop down list with the filers you want, and then specifying that from to be used for Grid Edit on some or all reports?
It is not an obvious thing, but you can create a dummy form which is just really a field list in sequence, and when you use that form for grid edit, then means that the report columns and the filters for drop downs would be taken from that dummy form. The form layout is ignored, its just a list of fields really and what report gets used for dropdowns.
