TIer 1 TO ILR for Dependent and Child Nationality

My situation.

-We came to UK on 20 Oct 2009 ,Mine is Tier 2(General) and my wife was on Tier2(Partner),Dependent.
- We switched to Tier 1 on 11 Jan 2011 (Valid till 11 Jan 2013)
- My Son born on 21 May 2012 in UK and his India passport got on 17 Aug 2012.
- My Wife traveled to India on 19 Sep 2012 with return date of 26 May2013
- I applied for My Tier 1 Visa renewal and approved 11 Feb 2013 for 3 Years.
-My wife and my Son was in India so they can apply for renewal only once my Tier1 get approved .So they applied on 25 Mar 2013 from India and got approved on 14 April 2013 and both traveled to UK on 26 May 2013.


Questions.

Quest ion 1 - Can I apply for ILR for both of us (Myself and my Wife) together as I have completed 5 Years and my wife was leaving with me in UK for 3 years since 20 Oct 2009 and went to India for 8 Month and living with since 26 May 2013.
Question2 – My Son born in UK and now if I get ILR can I apply for his Nationality after My ILR get approved.
Question 3 – If my Wife apply latter for ILR can she leave with on same Tier 1 Visa till 12 Feb 2016 even after I get ILR .

I have checked with Nationality services and they confirmed that my son will get Nationality without applying my son's ILR once I got ILR. I need not have to apply for my SON's ILR.