Way over budget mistakes, tenant stories, misinterpreted area comps, prolonged vacancies that could have been prevented?

If he's 50% off market and they have plenty of assets and cashflow to cover a prolonged vacancy, then the smart move is to re-trade.

I know little about owner financing, and to be honest, if I take on a 300k house payment (or even 250k for that matter), I would struggle to make the payment if I had a prolonged vacancy due to my current W2 income. 

1st tenant (that came with the house)- she is a Section 8 tenant and clearly knows the game better than me hence the prolonged delayed Marshall’s execution.I cannot have 2 Government assistance programs in the property at the same time since it is not a legal 2 family.

If you lost all your money, got dragged into a prolonged expensive lawsuit with a random group of other investors, and spent years digging the hole deeper before finally giving up, you'd be singing a different tune about syndications I'm sure! 

If financing remains expensive, focusing on high-cash-flow properties and strong rental markets will provide the best hedge against prolonged high rates.

A lot of people who have only bought 1 property and sold for a loss would rather move on with their lives than dealing with the headache and heartache of prolonged litigation.

If I can get around this situation, it would be worth carrying some costs for a couple months but if eviction prolongs, a good deal will go bad quick.

I do agree with you, when your margin of error is higher you don't have to be as precise which ultimately leads to waste in profits and prolongs your abilities to reach your goal if you are not disciplined.

As others have said you will get less return on your money and prolong the process, but your strategy will still work!