If a customer applied for a fixed rate loan but now wants to change it to an ARM, would we be required to issue a revised LE to properly disclose rate, payments, AIR table, and such that would change even if no settlement fees are changing?

Required? Technically, no. Of course, you now have to provide the CHARM booklet and ARM program disclosure, which are separate from the TRID requirements.

As for issuing a revised LE, there are those who will say "absolutely not," because it's not required and they don't issue "informational" LEs, because they can confuse borrowers more than inform them and because they would have to check eachy of the costs for good-faith and adjust them for any changes before issuing the revised LE.

There are also those who would send a revised LE because so much of significance will change with the change from fixed-rate to ARM. You'd find me in that camp.