I need to apply for my son's SSN by mail as we went to the US embassy in Edinburgh and they don't allow you to apply for this in person. The US embassy website lists several docs, and it's not always clear to me if they just want one in each category. If I'm right, I need to send:
-UK birth certificate
-CRBA
-Son's US Passport
-My US Passport (as the parent signing his application)
Do I also need to send in his UK passport as he's a dual citizen?
Also, I want to claim Child Tax Credits on my 2023 US Federal Return. Would the SSN arrive by the automatic 15 June extension if I apply on Monday, or am I better off filing for an extra extension to 15 October? I'm confused as to if I can even claim this for 2023 given he won't get his SSN until 2024 even though he was born in 2023.