You can make commission on selling your own investment properties and once your build a strong sphere of influence, the people you come in contact with like brokers, agents, clients, bankers, etc. can provide you with resources to make your investing a much more pleasant experience.

But the bottom line is your ability to socialize, influence others, gain trust and demonstrate your expertise and knowledge.

This "extra work" that realtors are doing is self-inflicted thru a legalized Racketeer Influenced and Corrupt Organization (RICO).

Well because your favorite YouTube influencer said so, and all the people on the biggerpockets podcast agree, and everyone else is doing this.

So, while I don't think the aunt has any legal standing to block the kids selling the house to you, she may have enough influence over them to do just that.

We will only see more influence with bitcoin and other technologies in this space 

Granted, there are variables that would influence and subsequently guide each member towards a different strategy but if there's some basic advice you can offer that would be great.  

@Steven Denio While they aren't directly about negotiations, Robert Cialdini's "Influence" & "Pre-Suasion" are good companions to Never Split The Difference, as they go into the how & why of influencing people's behavior.

GREAT LISTIf I may add a fewCenter of Influence Marketing i.e Mom Dad and Drinking Buddies (everyone in your Phone)Professional Networking i.e.

"Tone of voice and gesture can have a large influence on your ability to understand what someone is saying," Markman said.