You simply tell them not to do the work and that you will manage the rehab.  

A wise investor will not try to get rich quick with shortcuts.

I look for people who seem settled and want part time work and are available most of the day (maybe someone who does a night shift).

About 60k leads a month come through our clients sites in most every market in the US/Canada 100% online and it's a really consistent, but it does take some work and investment. 

Instead of resolving the issue, he’s threatening to place a lien on my property unless I pay him.I want to understand how does this lien work and this one example, I have such few examples with handyman, plumbers etc  they always keep threatening if you don't pay us we will put lien on your property. 

The numbers work and seems like I’ll be getting around $500 per door (cash flow) however I’m not familiar with the area and want to make sure is a good investment.

Here's a shortcut to get you 80% of the way there: do a google search in your local market and check out the top 3-5 property management companies.

While the state is tenant friendly, eventually they will be forced out and at that point it will be without the offer you gave them and with a black mark on their record making it harder to find another place.Since you are looking at flipping the property, you need them out to do the work and I would discuss that with them - not the flip portion but the work that needs to be done and can't be done with them in it. 

Owning C class or below property is a whole lot of work and risk.

The house needed around 30k worth of work and it appraised for 212k after renovation was completed.