Be conservative because demand can go up or down at any time as can the laws -- a good general rule of thumb for STR is to make sure it still makes sense as an LTR.

In a way, its not their fault, its just they have become so in demand and they cant hire fast enough to keep up, so the only way to keep growing is via price. 

I'm not saying "wow, what a deal" or to copy this I'm just saying when compared to SFH or continuing to rent, the 2-4 unit househack is very appealing and thus demand is strong.

Areas with good rental demand or up-and-coming properties could give you more predictable returns.Do you already have a type of property in mind—like single-family homes, or are you considering duplexes, condos, or other types of flips?

The seller would use this strategy when they don't have a lot of equity in the house.

Now, over a year and a half later, he sent a certified letter last week demanding the security deposit or legal action within 30 days.Please advise. 

Because it looks shady to most sellers, in a variety of ways. 

They can also give you a better idea of how much you should be prepared to pay so you can cruise through your closing with confidence.And as you plan ahead for closing day, be sure to budget for your real estate agent’s professional service fee too, in case the seller doesn’t cover it.

Sellers are in it to get the most money for their property.

I used to cold call sellers from across the countries, and offered to buy their homes for cash.