I maybe wrong but I'm not aware of DB changes being driven back to the database from an INT file during a structure change for example

Interestingly in the help for the INT file it says this about the Field_Name keyword in an INT file

This keyword is generally used to setup overlap column names. It can also be used to setup a different name for the DataFlex environment from the name at the server.

There are column names that are legal at the SQL data source but not in DataFlex. If you want to access a table with such a column, use the Field_Name keyword to set it to a legal DataFlex name. An example of this type of name would be File_Number, which is a legal name in most SQL environments, but is not legal in DataFlex.
So maybe it's not possible to drive everything from the FD file but it feels like this stuff should be in one place but maybe with all the layers that is just wishful thinking