Visa status for Tier 2 General dependent after main applicant switches to ILR

[ILR_doubts]

Hi
I am currently on Tier 2 General (from 10th June 2013, switch from T1-PSW to T2G) and my wife on Tier 2 dependent - both valid until June 2019. I am eligible to apply for my ILR based on 5 year route (Set O) from 14th May 2018 onward as I complete 5 years on Tier 2 General on 10th June 2018. I have booked a premium appointment for my ILR for 14th May 2018. My wife got her Tier 2 dependent visa back in India in Oct 2013 and she first entered the UK in Jan 2014. We are now expecting our first baby end of April 2018.
My questions as below -

1. I understand that my wife's Tier 2 dependent visa will still be valid after I switch to ILR? Is this correct? As we are planning to travel to India in Dec 2018.

2. When can my wife apply for ILR? Oct 2018 - 5 years from the time her visa was stamped or Jan 2019 - 5 years from the time she first entered UK subject to her qualification of 5 years continuous stay?

3. Our baby will be born in the UK couple of weeks before my (father's) ILR - baby due end of April 2018 and I (father) eligible for ILR from 14th May 2018). If I do not apply for baby's Indian passport for couple of weeks (as I have ILR premium appointment on 14th May 2018), can I register baby as British through MN1?

Thanks in advance for your help and apologies in advance if this info already exists on another thread. I have tried searching but wasn't able to get clarity on this.

Best regards
ILR_doubts

[CR001]

1. Correct, her visa remains valid if you apply for ILR through 5 years PBS route.

2. October 2018, visa start date.

3. Yes, MN1 once you are granted ILR.

[ILR_doubts]

Thank you so much. Really appreciate your quick response. Many thanks