Varying Tier 2 dependent Visa to ILR application

Current situation

I was on PBS dependent visa expired on 22th Jan 2020, applied for another visa extension just before expiry.
Husband already got ILR in 2019.
I will be eligible for ILR on 3rd April(28 day before 5 year completion)

So currently 3 year visa extension is still in progress and I am on 3C leave.
Also initial IHS surcharge paid was 600 because there was no option to pay for 3 years.
Now got an Intimation from IHS to pay the additional amount for full 3yrs by 15th of Feb. which i am planning to pay by 14/15th.

- Is it possible to Start an ILR application(Vary over existing Visa extension) around 17-18 before the visa gets processed and book appointment for 3rd April while the PBS visa extension is still in progress.

It seems your spouse is posting the same question using a different username ??!

indefinite-leave-to-remain/ilr-for-spouse-t292479.html

Sorry we were bit desperate to proceed quickly . Thank you very much for your inputs.