ILR long residence 10 year route circumstances

Complete History
Student visa granted 30/12/2009
Arrived in the Uk 19/01/2010
Student Visa expired 31/12/2013
Work permit applied on 27/12/2013
Work permit Granted on the 16/01/2014
Work permit expired on the 12/01/2016
Work permit extension applied on the 08/01/2016
Employer’s license got revoked visa refused on 30/06/2016
Admin Review applied on 11/07/2016 (within 14 days as per the letter)
Admin Review refused on 04/08/2016
Work permit applied with new sponsor 26/08/2016 (made the application within 28 days as per the rule)
Biometrics letter received on the 07/09/2016
Application Varied on the 12/01/2018
Biometrics letter received on the 19/01/2018
Work Permit Tier 2 Visa Granted on the 16/03/2018
Work Permit Valid until 16/01/2020

Questions
1. Please let me know if I am eligible to apply for my ILR Long residency on 10 year route?
2. Would there be any complications in my case?
3. Do I have to send any additional documents?
4. Do I need to know any other thing before applying?

Please guide me with my concerns.
Highly Appreciate
Thanks

1. Insofar as you never overstayed any leave (subject to the small grace periods allowed).
2. Not as far as rules were not breached or any adverse immigration history, KoLL required.
3. No, usually just passport(s) covering period.
4. As above.

Please clarify for me:

1. As my visa was refused on the 04/08/2016 and i applied for my new visa on the 26/08/2016 i had overstayed for 22 days which was still under 28 days as per immigration rules at that time, does this give a break to my 10 year long residency.

2. As i had Varied my application on the 12/01/2018, what is considered as the date of my application the first one i.e 26/08/2016 or the new one 12/01/2018, if its the new date, does it give a break to my long residence as my visa was refused on the 26/08/2016.

3. As my current visa is expiring on the 16/01/2020 and my 10 years complete on the 18/01/2019 as i entered the UK on the 19/01/2010, i am 2 days short of 10 years but as i can apply 28 days before my 10 years i just wanted to ask would there be any problem ?

1. As my visa was refused on the 04/08/2016 and i applied for my new visa on the 26/08/2016 i had overstayed for 22 days which was still under 28 days as per immigration rules at that time, does this give a break to my 10 year long residency.

Discretion is applied here

2. As i had Varied my application on the 12/01/2018, what is considered as the date of my application the first one i.e 26/08/2016 or the new one 12/01/2018, if its the new date, does it give a break to my long residence as my visa was refused on the 26/08/2016.

No breaks here

3. As my current visa is expiring on the 16/01/2020 and my 10 years complete on the 18/01/2019 as i entered the UK on the 19/01/2010, i am 2 days short of 10 years but as i can apply 28 days before my 10 years i just wanted to ask would there be any problem ?

No problem

Another Question:

I have filled up the application form, when i reach the payment page there is only the option to choose standard service, super priority service does not show can you please let me know how can i choose super priority service should i keep refreshing the page or should i try at a specific time, because i wanted to choose the super priority service for my application, please guide me, Thanks

As has been answered 100s of times, if you are not getting the super priority option, it means there is likely no availability due to high demand.