You sent a board to production without prototyping it first?
Anyway, to convert the Adafruit module to 3.3V operation, supply 3.3V to both the 3.3V and the 5V pin. I have no idea about your "routed" board, so I can't help you fix that. Perhaps you can modify it with jumpers.
No amount of testing can give you sufficient confidence when you exceed some specification, unless you are the manufacturer, with access to all the proprietary detailed information.
If you roll out a device that has 5V signals on a 3.3V limited pin, it will work or not work, but you will never be able to guarantee that it will continue to work.
One place you could intervene, is where the module pins meet the board. You could cut and re-route the 5V pin to the module, so it goes to 3.3V instead.