Citizenship for kids born outside the UK

Hi

Dad has just become a British citizen (this month). Two kids and Mum all have ILR now (since two months ago). I understand that Mum and kids can now apply for British citizenship without having to wait for 12 months...

Given the fact that I am slightly struggling with money. Option 1: I may apply for kids only (without Mum). Mum can wait until I have money...
Option 2: I may apply for Mum only (Kids can wait until I have money).

1-Which option make sense?
2-If I go for option 2, can kids be registered as British citizens while Mum is on ILR, based on the fact that Dad is British citizen? Or Mum has to apply with them so that they can be registered as British citizens?

Thanks

Either option works. One isn't better than the other.

They do NOT all have to apply together!!!