shahnam0716

I am just trying to see if I need to add a joint-sponsor. In that case, I want to prepare for it ahead of time to avoid last minute things. 

Not G325a but yes, include the information specifically asked for.  If you what to show evidence of when you were first in the same country, that's copies of passport pages, etc. submitted as supporting documentation/evidence, not a substitute for the information asked for on the form.

proof of domicile is needed even if the sponsor's address is in the United States. 
Plus, current paystubs of all the sponspors (wife if she earns money, wife's father, wife's mother)

Skype is the primary method of communication between me and my spouse for voice conversation. However, it seems like Skype is no longer available in UAE. Do you guys know of any other service that is available in UAE (whatsapp, viber, imo, none of these allow voice conversation)  

If you get an RFE and they send it to the wrong address you'll be in trouble.  That's about the only issue. 

USCIS as well as the Embassy will not expect nor require a couple living apart in separate countries to :
have joint account own property together have children  
Such items are merely suggestions, not requirements.  As for the affidavits, they carry little to zero weight in the overall evaluation of a file; I usually say skip them in favor of evidence of time spent together in-person.  However, based on your post, time spent together in-person may be something you don't have much of, in this situation, communication records such as emails, phone calls, video chats, social media, etc. etc. could fill some of this void as they show you regularly stay in touch despite being apart.
 
Sending gifts to family members while a nice thing to do, probably would carry much more weight if any at all than the affidavits.

I think you would put in your (petitioner) information in Person 1 and the relationship would be "spouse." Then, leave Person 2 and so on blank. 

NVC received our application in Feb 2017. They requested additional information in June 2017. We submitted the required documents in Sept 2017. In November 2017, NVC completed its review of our case and put us in the queue for interview. No updates on interview date yet. 
 
I hope this helps. 

I wouldn't think about expediting it with the request that you won't be able to support two households at the same time. Many spouses live separate from each other for months and even longer than a year.