CRBA India

[hindi_eng]

I am USA citizen acquired citizenship through naturalization in 2017. My wife is GC holder. We have been living in India from last 3 years. Travel to usa once a year so my wife don't lose her GC. We are expecting a baby in July. We have 2 option either to go back to USA and get baby delivered there and get the USA citizenship by birth in USA. Second option is stay here in India and have baby deliver here and then i US citizen father can apply for baby's CRBA and USA citizenship.

(1) Is there any disadvantage of getting citizenship by CRBA than having birth in USA?
(2) How easy it is to get the CRBA in India?
(3) I have been living in USA from over 21 years, how i can prove my 5 years of stay in USA? I have college transcript which proves 2 years. I file tax every year. For getting Citizenship i stayed in USA for at least 2.5 year after getting the GC, so i have exit and entry stamps in my previous passport, i printed my airline tickets. Is that enough? What solid proof i can collect to prove my 5 years.
(4) Can USA consulate decline CRBA of my baby because i am not white or i was not born in USA?

The reason we have been living in India is my mother who was going though the cancer treatment, and she just passed away this month, we are not in the condition to travel because my father is here alone. So we want to stay here with him so we all get used to this change in life. And then after the birth of child we will travel back to USA.
Your guidance is very much apreciated.

[JoeF]

Living abroad and traveling once a year is not and has never been enough to keep the GC. She has to actually live in the US. It is called Permanent Residency for a reason.