Do what many others from there have done, Ohio market, STOP WATCHING videos, total waste of time. 100s enough, take action :) 

Any news on Grandma's house yet?

If I go with this builder, what necessary actions should I take to ensure our contract is binding in case he defaults?

At a minimum you can have the satisfaction of knowing that the collection action will sit on their credit report for many years to come and may prevent them from harming another landlord.

if you did want to claim it, it would be better to revise the closing and get it included - then you are totally legal.Just realize your actions impact the other party as well.  

They kept getting rejected b/c sellers were hearing every night on the news about the blistering hot real estate market that had turned around and they suddenly wanted top dollar for their property, above what comps would justify, even above asking price.

Tim Bratz Is Here to Talk Mindset For Action!

Hi Braedon,Thank you very much, to be honest, the place where I started the business is what boosted the portfolio but with hard work, commitment and focusing on great service toward customers and owners alike. if you do a great work, then people will spread the news among their group and they will call you. 

I think you found yourself in the right place - soak up as much knowledge as you can but don't forget to take action!

It resulted in bad news all the way around.