JustXris

Question 3
 
 
Answer to Question 3
No, your spouse's child with their ex-girlfriend is not considered your stepchild unless you have legally adopted them. If you have not legally adopted the child, you do not need to include their information on your naturalization application (Form N-400). However, if you did list them on previous immigration applications (Form I-751 and Form I-485), this could potentially cause confusion during the naturalization process. You may want to consult with an immigration attorney for further guidance.

You’re right, only on the I-485 and N400 do they mention stepchildren. However, it is on the applicant to know that “children” for USCIS are bio, adopted, deceased, stepchildren etc etc. So technically they should have been mentioned. But in your case, my case, and OPs case it shouldn’t make a difference because those kids are already USC. 
I think the main issue is when the immigrant doesn’t list their own kids and then they want to bring them from back home.

My 751 is still pending, so I cannot say that I did not have any issues. But I am confident based on what attorneys have told me. 
 
Would you rather pay $150- 300 now but have peace of mind, or apply for the N400 not knowing whether listing him or not is wise? I don't know. I like simplicity and peace of mind, so if/when asked during my combo interview about my oversight in the I-485, I will explain it to the officer. 
I made a note on my 751 right on the form that says "he's my USC stepson" mainly because I did not want them to think that they would receive another 751 or biometrics fee for him. But it was just a note, not a letter.
 
I am not a huge fan of explaining unsolicited information. So I personally would not include a letter explaining yourself. I would wait until the interview, if asked. But I know that because I made several consultations. You should do the same.
 
Ask Jim Hacking on his YouTube show. He goes live tomorrow I think.

*** Moved from US Citizenship Progress Reports to General Discussion ***
 
 
List your stepchild on your N-400 to comply with the form instructions.  No need to volunteer any reason why you did not list them on your previous forms.  In the (highly unlikely) event that you get asked about it at the interview, just be truthful and admit that you did not realize that you had to list your stepchild.  I assume your stepchild is a USC.  If so, the prior omissions were not material info to your I-485 and I-751 cases.  That is, having a USC stepchild would not have been a significant factor in deciding your previous cases, unless your current spouse sponsored your GC and did not count the child in their household in the I-864.
 

On this particular subject, you will receive different opinions. Keep in mind that we are not attorneys. If you go by the N400 instructions, on page 9 it says:
 Item Number 1. Indicate your total number of children. Count all of your children, regardless of whether they are alive, missing, deceased; born in other countries or in the United States; under 18 years of age or over 18 years of age; married or unmarried; living, current stepchildren.
 
I was in a sort of similar situation, with some differences. But I also have a stepson, though he's a minor. I did not think I had to list him on my I-485, but when I started filling out my 751 and had to answer about children something rang a bell on me. So I consulted two or three different attorneys, one of which is a top notch one, and their answers agreed that "children" is a broad term for USCIS and stepchildren are your children. So, knowing that, I did include him in my 751 and plan on doing so this week on my N400. 
I know you did not include him before, but from my conversation with one of the attorneys, since your and my stepsons are both USCs, this should be a non- issue, because you are not granting him any immigration benefit. 
Actually one of the attorneys I asked is Jim Hacking. I was on one (or several!) of his live shows. I just can't find the clip.
 
You might want to consult with some attorneys, too. I just personally think it is better to be honest about a mistake you've made, than to be perceived as concealing information. My two cents.

Then she's an adult. Carry on with your own information. No need to mention kid