ILR - dependent eligibility check

Hi all

Quick timeline:
Entered July 2018 on Tier 2 ICT
Switched to Skilled Worker route on 11 March 2021
My daughter was born in UK on Nov 2020 → her child dependant visa was granted on 26 Aug 2021 (due to Consulate and COVID delays)
Absences are low – never more than 47 days in any calendar year(total around 120 days in 5 years)
Salary is above the proposed threshold.
Planning to apply family ILR submission on 11th/12th Feb 2026 (28 days before 5-year date). As per my company's solicitor, I can do 28 days before my eligibility date and they said, I'm eligible from 11th March 2026.

But my youngest daughter will only have ~4 years 6 months by Feb 2026(unfortunately company solicitor cannot provide advise about my daughter). Is it okay for her to apply with us? (Both parents are applying together and she’s under 18, UK-born + dependant visa). Hope we should use set(O) form for her/wife. Both are on dependent visa and we both cleared life in the UK test. We also have ECCTIS/NARIC cert for language proficiency. We have letters from school/nursery as proof of admission.

My wife has limited address proofs(2 per year for 4 years. Only for this year, she has more than 3). Can I use the letter came with BRP from homeoffice, which has our address & BRP number but no date, as an additional proof.

Children do NOT have a residence requirement for ILR. Children settle when both parents settle, as per the immigration rules. You all can apply together using one SET(O) application.

Read --> All you need to know about cohabitation evidence

Thank you so much