Tier-2 (General) visa extension under new rules

[gaurav7]

Hi,
I have been a member of this group since long and have been following the discussions. Thanks for all the info so far. Today I need some suggestions regarding Tier-2 General visa extension.
Me and my 2 dependants (wife and child) first came to UK on Tier-2 (short-term ICT) in Feb 2013, lived here for around 3 months only and then came back to UK on Tier-2 (General) in July 2013 and this visa expires in July 2016. I have following questions:
1. The maximum allowed time on Tier-2 is 6 years. Will the duration from Feb 2013 to Apr 2013 (on Tier 2 ICT) be counted within this time or only Tier-2 (General) duration i.e. from July 2013 be counted towards that?

2. Due to major changes done every year in immigration rules on 6th April, we are planning to extend our visa before April 2016, to be safe. Is it fine? Also, how long we should apply visa for? I believe it's fine to apply for 3 yrs extension (around March 2016 to March 2019), that gives us sufficient time to apply for ILR in July 2018.

3. Is it advisable to apply for full family in one go or I should go first and then the dependants?
4. I hope getting Maternity leave and pay are allowed under Tier-2 General dependants category?
5. Any idea about how much "NHS surcharge" we need to pay under new rules?

Thanks
Gaurav