ILR from tier 2

Hi,
I'm applying for ILR from tier 2 and including my wife and my son in my
application (currently they are my tier 2 dependents). I have some
questions about the SET(O) form:
1- Can I include my dependants in the same application or I need to submit
separate applications for them?
2- What supporting documents I need to submit (specifically do I need to
submit marriage and birth certificates? should the evidence of cohabitation
cover the 5 years or up to 2 years as mentioned in the application?).
3- Does the 5 years start from the date entry clearance was issued
(23/09/2012) or the date we entered the UK (17/10/2012)?

Your help is highly appreciated.
Many thanks in advance.

1. One form for all of you together.

2. Read the guidance notes. Cohabitation for 2 years.

3. Entry clearance date for your BUT it is the date of ENTRY to the UK for your dependents.

Thanks very much for your reply.

I went through the guidance notes but was not able to find the answer to my question which is: Do I need to submit marriage and birth certificates of my dependants? They have been granted leave to enter and leave to remain as my dependants.

Could you please help?

Can anyone please help answering my question: Do I need to submit a marriage certificate and a birth certificate for my wife and son who are applying for ILR at the same time as me (they are currently my tier 2 dependants)? And if yes, do I need a specific certified translation for these certificates as they are not in English?

Many thanks in advance.