General Green Card

My spouse has her green card from 2014 and she has been travelling regularly to India to take care of her ailing Father.
She had been coming back to USA within Less than 6 months and staying in the US for a few months
and travelling back again. This has has been going on for the past 6 years. In between she got a reentry permit for 2 years which has expired.
recently she travelled back to the US after 8 months and had a tough time with the immigration officer who questioned regarding the
extended stay in india and finally she was allowed in with the regular stamp in the passport. No comments/special notes were made in the passport.She has now applied for a new re entry permit and waiting for its approval.

she co owns the house and a partner in the LLC and has been filing US resident taxes and I have
been working and staying in the US during the entire period .

1) Based on the above details is it safe for her to travel once her re entry permit is approved?
2) Should she wait for a specific period of time before she can travel ?
3) Would carrying a copy of the House title,LLC partnership details and copy of the Tax filing help
in case she is questioned at the Port of entry.

1) Please list out what are the documents need to be carried for final interview by main applicant and the dependents?

2) What are the general questions we can expect from the officer during the interview who makes decision and how the interview process will be, so we can be aware and prepare ourselves?

I am planning to file green card (I130/I1485) for my mother. She was born in 1949 in India and does not have her birth certificate. Only identity with date of birth she has is her passport and Aadhar card. She has visited US couple of times.

1. I want to know is it required for her to submit birth certificate or a non-availability of birth certificate for I485?
2. What are the options if these documents are not available?
3. Does USCIS accept birth certificate from the Indian consulate in NY?