ILR question

[yylifeintheuk]

Hi all,

I know there are still years to go but I would like to know about the answer for the ILR application.

Me, my wife and son apply tier 2 and tier 2 dependents at the same time at received the same outcome at first application.

We got on visa sticker:
valid from: 24/12/2017
valid to: 23/01/2018

In the letter together with the passport to collect BRP, it stated.
Your application for UK visa has been successful. This means that when you arrive in the UK you will have permission to be in the UK (known as Leave to Enter) as TIER 2 (GENERAL MIGRANT) (for mine)/PARTNER (wife)/CHILD(son) from 24 Dec 2017 to 14 Jan 2023.

It is more than 5 years, so definitely no problem for ILR application. However, I am the one enter the UK first and collect my own BRP, wife, and son join later and they applied for the new visa vignette, when they apply they need to submit the original letter, they took the old letter and give the new letter, the new approved visa vignette and letter with a new date:
Your application for UK visa has been successful. This means that when you arrive in the UK you will have permission to be in the UK (known as Leave to Enter) as TIER 2 (GENERAL MIGRANT) (for mine)/PARTNER (wife)/CHILD(son) from 20 Mar 2018 to 14 Jan 2023.

They entered UK 22 Mar 2018 and collected BRP, the BRP date starts from 28 Mar 2018 to 14 Jan 2023. From the new date, they do not have 5 years in the total duration. When entering the UK, the customs officer use pen to cross the old visa vignette.

Question:
1) For my wife and son, is the start from date calculated from original 24 Dec 2017 (the date they absence from 20 Dec 2017 until they enter UK 22 Mar 2018 counted as holiday?)? Can they apply ILR together with me after 5 years?
2) Or the valid date start from 20 Mar 2018 (on visa vignette) until 14 Jan 2023? If this is the case, they will need to apply for another tier 2 visa extension before they can apply ILR because do not meet 5 years requirement?

Thanks a lot.