Also no guarantees on investments and I think they are using investor's money to keep the mass payroll going etc. meantime.

From what I understand a PEO is a company that hires, takes care of payroll for businesses and also gives worker's comp and benefits.

If she is not a member of the LLC then one disadvantage of not having her on payroll would be no stated income.

where to define roles and to what level of detail (banking, tax filings, payables, payroll, rental operations (screening, lease agreements, etc.), business operations (phones, facilities, BiggerPockets subscriptions, etc.)"

Is anyone on payroll?

And that is with a sophisticated investor, granny needs a 3rd party advisor IMO as the RE investor/operator will never be believed that granny clearly understood risk.

Procter & Gamble, one of the largest and most sophisticated advertisers in the world reported:A year ago P&G announced that it would move away from ads on Facebook that micro-target specific consumers.

It is much more sophisticated than it seems.

It is also a more complex/sophisticated value add that likely should be attempted by experienced RE investors that are OK with some risk. 

People in these organizations are typically semi-sophisticated so selling on a land contract probably won't scare them and they may even look at it as a benefit.