will applying for an ILR allow me to stay and work in the UK till the decision on ILR comes?

[RahulSS]

Hi Everyone,
Apologies if I am asking a question which is already answered on this forum.

I am completing 5 years in the UK in April 2019. Arrived in the UK in April 2014 on 3 years Tier2 General VISA which was extended in 2017 for 2 years and expires on April 2019.

My question is:
1) Should I apply for another extension of 1 year in Jan/Feb 2019 and then apply for ILR in April 2019? Is that advisable?
2) If I don't go for a year's extension, will applying for an ILR allow me to stay and work in the UK till the decision on ILR comes?
3) Does going for a premium service for an ILR application help?
4) If the ILR is refused, how soon I need to leave/depart UK? 60 days, 90 days?

Your help and knowledge are highly appreciated, thanks in advance.

[CR001]

There is no need for duplicate/multiple topics asking the same question!!

indefinite-leave-to-remain/tier-2-to-il ... l#p1640524