Hi, I'm in discussions with the seller's broker on putting together a master lease option. 

The only way it gets better is if you acquiesce to their demands, OR make them go away.

I don't think they necessarily have the best rates but they are who I have used for my 2 properties (one of which had a seller carry-back and construction loan too).   

The more common mistakes are buying incorrectly, not planning for capital expenses and the cost of money and underestimating operating expenses or having the seller lie on his T-12.

You're assuming the wholesaler can't close the deal themselves, while that's certainly possible, you can't really say for sure without knowing what kind of contract they have with the seller and what their financial situation is.

A ton of money has been made on B-C value-add apartments in the 2012-2016 period because of the tremendous demand and rent growth. 

Add that to your current 15K, you have a lot of liquid cash to invest multiple properties or a nice MFH in an in demand neighborhood.

Distressed sellers. 

For instance: I have 1.5 acre lot with a $5k accepted cash offer from the seller... tax value is 30k and based on comps looks like 20k would be doable.

Assuming that the grandson is not living with the dog then I would think that you can demand that the dog go and......obviously, the grandson doesn't need a service dog!