How do I protect myself against this in the future?

An M2M lease still provides both parties an agreement and protection. 

Someone that might drive away a potential customer for unit B.

Most experienced investors aren't looking to the protection of a home warranty, which gives me another level of caution. 

I am thinking of using online banking with no minium but I keep hearing stories its customer service is nightmare? 

I think what is becoming more and more important is having a solid investment thesis and understanding of your target market and the value proposition you are offering to your customers through your properties. 

They think they can hide behind custom contracts and lawyers. 

Contractors are frequently working multiple jobs - and if they know you are out of town investors - how much priority is your job to them, versus meeting with other customers for their next job or finishing people who have their eyes on them.  

Will protect the higher cash equity as its money out of pocket.. and the equity is more real or tangible its not phantom. 

An LLC is just an entity you use to protect yourself against liability.If you have the opportunity to buy in your backyard, I would.