Gi Deon

I think you should upload it just to be safe. I am the petitioner. They didn't ask me either. But I sent it anyway, just in case. As a matter of fact, because I was married before, I sent my divorce decree, and marriage certificate. Only to explain why I had a different name other than maiden. I figured they would have asked anyway. I strongly believe that because I sent that, they approved us so quickly and didn't request more documents. Which would have taken more time

No need

2x2 size (inches). 

Passport style photograph

Then they both use separate I-864 forms.  Wife is petitioner.  Sister is only joint sponsor.

Read the instructions, also here's the guide
 

In addition to what have been mentioned above, pay stubs. If petitioner is currently residing outside the US, submit proof of domicile.

It depends on what is being used to prove you meet the requirements.  If using income from a current job, then income tax returns or tax transcripts (IRS tax transcripts are generally preferred) as well as proof of employment (letter from employer).  If using assets then it becomes a little more complicated as you have to show valuation of the assets.
 
Good Luck!

Hey y'all. Hopefully this update helps someone down the line. 
 
Last week: 27 OCT 2020
DH had his interview and was approved that day. 
Interview review is here: https://www.visajourney.com/timeline/profile.php?id=365540
 
The follow day his visa was issued. And arrived the next day after that: 29 OCT 2020. 
 
We promptly paid the the final USCIS fee (about $200-ish bucks). This is paid directly to USCIS (when you get to this stage the website states you should pay before entering the US, however if you don't, they will send you an invoice in the mail and it will inevitably delay your GC and SSC, if you opted to get one at the petitioning stage... we did). 
 
Booked a flight from London to Kentucky, by way of Chicago. We did this because we already know Chicago's immigration vibe, so it would be familiar for Mr. Idu. 
 
The flight was on Sunday, 01 Nov. 
London airport - bit of issue with bag weight, easily solved, they were a bit confused with what to do with visa... however it was sorted and one of the officers finally came 'round and handled it all. Please note that IR-1s (and I'm assuming CR-1s) will have two exceptions listed on your visa sticker: 1-for the travel ban on working in the US, 2-for the travel ban on immigrating. They are plainly written at the bottom of the visa entry sticker. Mr.Idu also had documentation to prove our relationship, but wasn't asked for it. London done and dusted. 
 
Chicago airport - easy peasy. Went through immigration smoothly. They stamped his passport and wrote the a-number again. 'Welcome to America'. 
 
The rest is history. We are reunited! Finally...after a delay over the summer due to covid-19. 
 
Good luck to everyone! Things moved very quickly for us in the last few days. So hopefully that same energy will be the same for y'all. 
 
Now we're just awaiting the GC and SSC. 

Starting over with a CR-1 probably wouldn't be faster, of course that depends on the backlog for K-1 interviews in Paris and how soon they start scheduling interviews.  With the lockdown in France and uncertainty of how long the pandemic will affect K-1s there, no one knows for sure what the comparative timelines will be.  If I were in your situation, I wouldn't worry so much about "faster" as right now nothing is fast with US immigration given the pandemic.  I would make the decision on whether it is important for your partner to be able to work, travel outside the US immediately on arrival, vs. the K-1 restrictions, long wait for EAD/AP, and the whole AOS process vs. the CR-1 which has so many advantages.  Either way will take a long time so make a decision based on other factors.  Good luck whatever you decide!

Thank you!

Mine is IOE too... maybe it's really a technical issue for IOE receipts.

Hard to tell why you're getting this.  Be sure you are properly entering the case/receipt number with no spaces in or after the number.

I usually get that error when I first land on the page.  Click "OK" then enter your case number in the box.  Then click "Check Status"

I've been getting that today...started in the afternoon.
 
Now I'm seeing this:
 

When you are in tough situation like this, don't travel.

I'm not your sweetie and yes that's how it works 

Have she tried calling USCIS or sending an email?