Thanks for the reply Supine.
I checked and double checked because I am paranoid like that lol.
It looks like I don't need a transit visa because Indonesia is not listed in the "need transit visa" countries. But I am just wondering what happens if let's say everything went smoothly but the outbound flight from FRA got stuck... say 12 hours.. What are my options? Can I go to the lounge inside (without passing through immigration) and pay a fee to rest/shower?
I took this same flight a long time ago and remember it was pretty painless but I don't know what have changed now especially since Covid happened.
My kids will be fine since they have American passports.
Any additional info about this flight and the airport system itself is definitely appreciated.