FLR FP renewal complication

[Junior123]

Hi i will try to keep this short as i can.

I have been granted FLR FP 10yr route as parent. X wife and i separated nearly 7 years ago. we have 4 children age btw 7 and 12. both born and raised in uk. x wife and children's were granted 10 year route private life prior to myself.

x wife did not extend their visa on time, she later on submitted their application late then later on Oct 2020 withdrew the application before decision was made and left the country and gave up the family home where she lived with the children.

I had to become the primary career, take children into my care, we are currently homeless and in process of being homed by local authorities and social service, i have access to public funds, and recently started receiving child benefits plus universal credit top up as i work fulltime.

My visa renewal is coming up in April. and i need some advice of how to go about it.

-my children currently have no visas - through no fault of my own
-1st two born are qualified for Naturalization as the both over 10yrs born and raised in uk but cant afford the fee for now.

would it be okay if submit a fee waiver for both me and the children now and hope we will get an answer before my renewal date in early April?

Then if granted then submit both applications mine and the children as extension?

or do the children need to have the Leave to remain valid before i can extend mine? which i don't have enough time to apply for theirs before mine expires

we cant afford solicitors and any help or advice will be greatly appreciated, many thanks in advance