A database always has fields that are empty so what you propose is what already exists.
Secondly I believe Filemaker maintains a numbering system for fields plus a 'lookup' table for whatever you name the fields which is why it is so easy to rename fields and have things continue to work, unlike other database applications especially xBase.
There are control characters used by Filemaker and you should avoid using these in your field names.
Preceeding a field name with a_ or b_ etc. should cause no problems and make for easy sorting. It will however eliminate the ease of field labeling when the field is dragged on a layout.
Instead of ===Time use ___Time
Maybe someday Filemaker will add Folders to the Field editor? Who knows what problems that will solve....
I wish there was something that could be done here. Folders is an excellent idea!
Find myself resorting to a similar system proposed by Wladdy as a hack workaround.