Juniser

Having a child makes a difference with the medical in Moscow.  I forgot the actual test that they do, but it will be in the instructions you get.  That one test for the child requires 48-72 hours before med docs are ready for embassy.
 
We had Moscow Embassy appointment on a Thursday.  This did require the first medical visit on Monday.  This is where they applied something to the child's skin on their arm.  We were told to come back Wednesday after 48 hours for the doctor to check the arm.  If there is hardly any reaction, they will finish the medical docs, and in our case because I was an American who was there (I think), they gave me the sealed medical docs to take to the Embassy.
 
I don't know what the options are if there is some kind of other reaction to the child's special test.

We stayed at the Radisson Slavyanskaya Hotel.  Everyone speaks English there.  Great breakfast and coffee.  Nice pool, hot tub and spa.  Right next to Kievskaya metro station.  Takes 8 mins on Metro, then 10 min walk to Embassy.
 
Close to the medical administration (your first visit) and medical hospitals (for the actual medical exam).  Close to Arbat Street acros the river.  Right next to Europe Square mall full of anything you might need to get or eat or buy.

I had the exact same situation.
 
Do not worry.  Very simple to solve this.  I had to do this as well.
 
Keep all your I-129F documentation consistent as it is currently with: "Kseniya"
 
Keep her Russian international passport as it is currently for the I-129F documentation with: "Kseniia"
 
What really matters at this time for the I-129F approval is that the Cyrillic spelling on her Russian international passport and her Russian Documents exactly match, which most likely is "Ксения". Very unlikely there will be a problem with English transliteration at the time.
 
When you get your I-129F approved by USCIS, it quickly goes through NVC and onto US Embassy Moscow Consular processing.
 
The US Embassy Moscow when processing/issuing the K-1 visa surname would have no choice but to use the English spelling "Kseniia" that has been put on her Russian international passport by the Russian Government, and thus, put "Kseniia" on the K-1 visa.
 
If you want "Kseniya" on the K-1 visa and subsequently on your USA Marriage certificate as her maiden name, you will need to get a new Russian international passport with "Kseniya".  The good news is that you have enough time until the I-129F is approved to get a new Russian international passport with "Kseniya".  This is my suggestion because 1) your wife will be happier, 2) the English maiden name will be on the USA Marriage certificate that came from the K-1 visa which is then put in the USCIS alien registration system that assigns your fiancee alien number.  It is a snowball effect you can easily solve right now with a new Russian international passport with "Kseniya".
 
So with the new Russian international passport with "Kseniya" and after the I-129F approved petition finally gets to the US Embassy Moscow, you will be filling out the DS-160 visa online application using the new Russian international passport number with surname "Kseniya".  This is the part of the process that really matters for the correct English surname for the K-1 visa that will be inserted into the Russian international passport with surname "Kseniya".
 
To summarize, now is the time to go get a new Russian international passport with "Kseniya".  Plus, any RFE that comes from the I-129F process would be answered as well the with having new passport with "Kseniya".
 
Here is another point to pass along that my wife and I conscientiously do:  We keep my wife's name as is (maiden name) on all Russian documents, property, etc as time goes on.  President P made a law for all dual citizen Russians (including green card holders) to register on a Dept of Migration list.  My wife refuses to do that and it is more covert to have a Russian surname (for example her maiden name) left as is on her Russian passport and to have my surname (husband) on her green card and future USA Passport. 
 
So in my opinion, having a new Russian international passport with "Kseniya" is a document that you will be keeping and not changing again AND your wife will be happier.
 
 
 
 

Here is the statement in your NOIR:
"Consular Post confirmed through the Pakistan's National Database Registration Authority (NADRA) that the beneficiary is still married to his claimed ex-wife ..."
 
In plain English your NOIR is saying that it was determined that he was still married.  That is the decision made by that Consular Officer.
 
You have to accept what has been decided by the Consular Officer and seek professional advice on how to proceed.  I am just trying help you understand the #1 problem in the NOIR.
 
 

Here is the statement in your NOIR:
"Consular Post confirmed through the Pakistan's National Database Registration Authority (NADRA) that the beneficiary is still married to his claimed ex-wife ..."
 
In plain English your NOIR is saying that it was determined that he was still married.  That is the decision made by that Consular Officer.
 
You have to accept what has been decided by the Consular Officer and seek professional advice on how to proceed.  I am just trying help you understand the #1 problem in the NOIR.