Yes, I wish there was an app or a site where you can easily find out the property tax on rentals instead of going through the assessor’s office, 

You could easily buy a turnkey home through a company like mine, Real Wealth Network, and its the same thing minus the 15% fee.

Scanning and Digitizing Physical DocumentsAbility to easily scan all physical documentation (previous data and present data)6.

I could easily make 10-20% on a rental property.

My biggest fear is that if I ever were to quit my job, I would no longer be able to invest in more real estate (not sure if I would qualify for loans as easily). 

.-  This is a product which is easily raised, harvested and milled in Belize. 

Can you easily add a bedroom without making the flow feel weird (i.e. accessing one bedroom by going through another) or taking away from common area making them feel small?  

If you want to scale using the BRRRR method I could send you a list of properties in terrible Philadelphia neighborhoods where you could easily complete the BRRRR and yes, you could theoretically "scale".

so closing costs by themselves could easily be $12-15K. 

The beauty is that you can easily change your mind on this issue in the future.