FM - Is There a Way to Make a Value List Dynamic?

I think your first question is really asking, "is there a way to force and update of the existing entries on all records for a specific value list value when the user edits the value list itself?'

Assuming I've restated the question correctly, the short answer is that there is no built-in way to have this update occur, especially if you are using File -> Managed -> Value Lists and editing the custom values. You can setup a separate routine or manually use the Replace command, but FM will not replace one value with another automatically when you edit a custom value list.

Value lists however can be based not only on a user specified "Custom Values" value list but also on existing values in the actual field being edited or in another field. If the Value list is set to show only values that already exist in a field (rather than Custom Values), you can create a script tied to a button or menu item that presents a Find/Replace dialog which then does a Find for all records with that value and performs a Replace between the two terms. The Value list should then only show the new Term. Care must be taken with this approach so as to Replace the [entire value rather than just part of an existing value. You have to error check for values that may already exist in whole or as part of other values. e.g if you have two towns, Montague and Montague Center, performing just a replace on the word "Montague" will also Replace the "Montague" in Montague Center unless you setup the calculation to Replace the value of "Montague¶" rather than just the word.

Another way to make flexible, dynamic value lists is to setup a table with the value list values and serial numbers. Change the value assigning system so that when you select the value, you are actually assigning the Value's serial number rather than the value itself.

If you give the user a portal in which to edit these values, then they can edit them to their heart's content and the values will update across the database because the serial number remains the same as with any related record.