ILR dependent visa

I will apply for ILR on April 2023 ( Tier 2 , 5 yrs route ) . My wife and 4 children will be eligible for ILR on September 2024. They are all now on Tier 2 dependent visa that will expire on September 2023 (was annually renewed) . My question is :
After i get my ILR in April / May 2023 after using priority service, can i apply only to one of my children(16 years) for ILR dependent visa rather than waiting till her current Tier 2 dependent visa expires in September 2023 ? and if i can do so, for how long she will be granted ILR dependent visa? Will it be till she completes the 5 years period in the UK .

The child must apply for the same visa extension category as your partner. They all apply for a PBS dependent visa extension.

The children can only apply for ILR when your partner does.

Sorry this was my bad to explain. I meant can i apply for my daughter (16 yrs) for PBS dependent visa on her own in May 2023 considering her Tier 2 dependent extension will expire in September 2023 and if so for how long she will be granted the PBS dependent .
The reason i ant to apply earlier as there is a school trip in September to Europe and she needs a valid visa before that .

Regards

You must apply for all dependents at the same time and you can apply for all of them in may.

You cannot apply for her on her own as new visa for her will only be valid till your partners expiry visa in September 2023.

That is really helpful . Just two last questions
1- When i will apply for them in May 2023 for PBS dependent after i get my ILR , will i pay the same amount of fees i used to pay for them (£247) as iam health care worker or the fees will change once i get ILR?
2- One of my children is 20 years old and studies abroad . Can she apply on her own in September 2023 if the rest of the family applied in May 2023 ?

Very grateful for your response