Not sure about PCP letters. They asked me to get a medical clearance 3 months before surgery from my PCP and provided the forms for them to fill out. It wasn't really a letter more just a statement of being healthy enough for it.

Therapist - as long as they don't have a time between appointments req listed and they didn't discharge you it shouldn't matter.

Gender Dysphoria typically with code F64. 0 is what surgeons/insurance wants to see. If there's comorbities they can list those codes too.

You will need new letters if the requested information is different or if the old letter was addressed to the surgeon. Also surgeons sometimes want surgeries dated within the last year.