Severance

I have some questions because I recently started watching so I may have missed a lot of details.

-Why do people give birth in a severed cabin, is it to forget the pain of birth?

-How did Irving get all that info on Lumon employees?

-I thought Mark had his chip removed but he seems to not be reintegrated.

-What is the small bottles of baby food in Marks refrigerator?

-Is it ever mentioned what Lumon produces/sells today other than ether?

-Is it ever mentioned or explained how Lumon/Kier went from business owner to cult figure?

I'm not sure if this stuff has been explained and I missed it or if it's purposely left vague for the mystery.