Future ilr application

[Bilal123459999]

Hi everyone
Long story short me 19 year old my brother 16 and my mum just got our flrm visa approved .main applicant is my dad now after 2.5 year we gonna apply for ilr .Question I wanna know about that
1 Is the financial req gonna be same as flrm I mean last 6 month payslip
2 I am 19 and if I work full time am I still going to be able to get ilr same with my brother who's gonna be 18 and I 22 at the time of ilr application
3 can my dad who is a British citizen can he claim working tax credit as he did claim child benefit before for my bro but we stopped because our solicitor said so