Now that co says their ins wont cover a claim for repairs bcuz they didnt authorize it.

The fact you learned the children are the ones selling the property through a neighbor and this was not clear in the sales agreement suggests the proper authority might not have even existed to execute the agreement on behalf of the estate in the first place. 

Please check out the book I co-authored called Lend to Live: Earn Hassle-Free Passive Income in Real Estate with Private Money Lending published by BiggerPockets.com/lendtolive.

If you promise them a "rescue" and you don't get it done before the foreclosure sale they can sue you and the local authorities can investigate you.7.

Was the sewer authority being paid in the past and who was the seller using in the past for the septic service? 

Hi Account Closed is clearly an authority on the San Jose rental market on this site, so I would definitely take note of his posts on the subject.

Can you recommend any nice areas in LA for house hack for similar amount of capital as the author of the post?

Depending on what the Rental Application authorization states the applicant is allowing, the PMC may be able to give you access to the applicant's DL, paystub, etc. info.

Any change to the fees or entities listed in the disclosures provides to you an immediate authorization to cancel with for refund of all earnest money ….

Do note that you will need to obtain signed authorization for recurring debits and must operate in compliance with NACHA's rules.