Holliver

I would say go ahead and file the I-131 for travel anyway. You never know when an emergency can pop up. It is true that you can still file for it for free after sending in the I-485 by just including the NOA receipt from your I-485 filing. However, it takes 2-3 months to get it, same as for EAD. If you file the EAD and AP at the same time, you will more than likely get an EAD/AP combo card, good for work and re-entering the US.
The I-131 is short and easy to fill out. Just fill out Part 1, check d. in Part 2, fill in Unknown for the travel dates and length in Part 3, skip to part 7 and check the box for more than one trip, leave the rest blank and sign and date it in Part 8. No need to include a statement as to why you should be allowed to get the AP. That is not required when adjusting from a K-1. Include 2 more passport photos, another copy of the K-1 visa and copy of the bio page from her passport to go along with it. Not that much to it, and then you do not have to worry if an emergency comes up.
Your other documents look good. You should also include a copy of the bio page from her passport for the EAD. Are you self-employed? Is that why you are only sending in the tax transcripts with the I-864 and no other proof of current income such as letter from employer and recent pay stubs? Other than that, it seems you are good to go.

No problem. You don't have to find a locker, the guards will take your mobile. They have plastic trays where you can put your electronic stuffs. Switch off your phone and if you have any metals like keys and coins you also have to put them in a tray for the security screening. My appointment was 8:30 but I arrived an hour earlier. I suggest you go to the embassy 30-45 minutes earlier and don't forget to bring your appointment letter. You're not allowed to bring food or drinks but don't worry they have a vending machine inside The interview has 3 stages: pre-screening, fingerprinting, and the actual interview. The entire process took 2 hours for me but most of those times were spent waiting for my number to be called, the actual interview only took 5 minutes though.
Your interview is on Tuesday right? Is it holiday on Monday?

And oh, if you didn't memorize your fiance's address and phone number, write it down in a piece of paper so you won't have to go through all your documents when you fill out that piece of paper they will give to you before you enter the visa section. Good luck on your interview!

Yes. the vaccinations acquired before or at the medical are put into a document - that document is the link I provided.
When the vaccination record is incomplete in home country you'll need that piece paper and take it to a civil surgeon in the US - either to first get the last vaccinations and then to have them added to the vaccination record, Or go to your family doctor and get the vaccinations and proof of it(receipts) and then take that and the vaccination record to a civil surgeon and have them transcribed. A full exam isn't needed when doing AOS within a year. Keep calling until you find someone who'll just do the transcribing. It's less expensive.
Bottom line, if it's cheaper to get the shots in home country don't wait. But do indeed get a copy of the vaccination record no matter what you choose.
Congrats on visa then

Expect they don't already have everything. Even though they already has proof of the petitioner being USC, bring copies of it anyways - it's needed for the i-134 nonetheless. As for the rest; you don't need to bring 10.000 papers of chatlogs but atleast bring something to show a consistent ongoing relationship whether it's visiting each other or phone calls, emails/cards etc. Bringing the i-129F petition with everything in it is required at some embassies, recommended at others. If they're missing something, you're ready to submit it right away.
..and as mentioned, read from fellow countrymen having gone though the embassy - embassy info as well as reviews.