Let me just get this straight what I meant was if we went down to the post office now to get this BRP and then we have it ready for the visa application process when we send that off in May.
The BRP (Biometrics Residence Permit) is your visa, you so you can't get it until after you have applied for it in May.
Instead of getting a visa sticker in your passport, this time when you apply there will be no sticker, your visa will be issued as a plastic BRP card.
The way it works is:
Apply in person (£500 extra)
- attend an in-person appointment to submit the visa application and documents
- your biometrics are taken at the appointment
- the visa decision will be made that day
- your BRP card (your visa) will be mailed to you within 10 working days
Apply by post
- mail your application and documents to UKVI
- about 2 weeks later you will receive a letter inviting you to get biometrics done at a local post office. You must take the letter with you, or you won't be allowed to get them done.
- when you have given biometrics, they will be sent electronically to UKVI, once they receive them, they will start processing your application
- when the decision has been made, the BRP and your documents will be mailed back to you
We are actually wanting to get our 2 little girls their american citizenship should they ever want to go live in America when they are older so maybe thats a feasbile thing for us to do although timing 3 appointments may be a nightmare there!
Your children already have US citizenship, simply because your husband is a US citizen, so what you will actually be doing is making an appointment to register their births abroad and to apply for their US passports.
Why not just make the appointments at the US Embassy for them now? That way, you can get it out of the way a few months before you need to worry about applying for the visa.
See:
https://uk.usembassy.gov/u-s-citizen-services/birth/