Film New Orleans is showing that Bill and Ted Face the Music is scheduled to shoot in News Orleans June 24, 2019 through August 17, 2019.
For those on the ground in New Orleans who may be interested in working as an extra, the site gives a list of local agencies that you can register with. Note, I have no idea if B&T3 will need extras, but if they do you will nee to be registered with an agency to see the casting calls and to apply.