When touring I carry a spare tire. Plus tire boots in the saddlebag. On at least one occassion I had a tire blowout and it could nto be booted. I think the bead gave way and the tire would not stay mounted anymore. So a new tire was the only choice. Carrying boots and a spare tire is wise.
I'd suggest using thread locker on bolts and screws on your bike. May not need spare bolts or screws if you use thread locker. Thread locker keeps bolts in place.
Rear derailleur hanger? I suppose since your wife and you have the same bike then its easy to take a spare hanger. But otherwise, skip it. You can always rig the bike up single speed if the hanger breaks. Assume you have a chain tool in your kit to shorten the chain and make it single speed length.