I am a custom staircase maker and have been blessed with the ability to binge real estate investing books all day at work, and finally got hooked on the bigger pockets podcast as well. 

Because the market has good growth fundamentals. 

So yes, I'd say locals have an advantage in their ability to scale in some situations.

Does having one mortgage affect my ability to get a second for myself? 

A lenders main concern is your ability to repay the loan, if you lived your own they deemed you not able to.

The act of making a counter offer in writing, by law, voids their original offer and they are absolutely no longer obligated to it.Even if you hadn’t voided their original offer with your counter, there is no ability to “sue them to force performance”.  

Perhaps they didn't understand the effects of the growth on the unit. 

Some allow you unfettered ability to advertise (so long as its truthful), some allow you limited ability to advertise certain things (like your business generally but not an offering), etc.

Yes, free-and-clear owners. 100% equity = decisions making ability. 

I'm not too familiar with that area but it doesn't appear to be a major growth city.