FYI - please tell your alternate leaders to check their spam box as soon as you apply. They only have 3 days to accept. If they don't accept within the timeframe, you will have to cancel your application and pay another $6 to reapply eek . This happened to me. I couldn't find anywhere on the Inyo NF site that said this and their office was not very helpful. All I found on their website was this:

Alternate leaders must now confirm that they accept the responsibility to be an alternate and can only be designated at the time the reservation is made.
When you make a reservation you have the option to select up to 3 other people to act as alternate leader on your trip. You must enter a valid email address for each alternate. They will receive an email and must respond and accept being an alternate within 72 hours or they will not be allowed to pick up or use the permit. If alternate doesnt have a recreation.gov account, they will be required to create an account. Alternates cannot be changed or added later. Being an alternate carries the same responsibilities as the primary permit holder. Please review leader responsibility.