I met both tenants several times and spoke with them prior to this and felt comfortable with it.  

I kept that license active for about 30 years.Regardless of what I had, I felt more comfortable with the construction business.  

Goals -Refinance soon-  I planned on going 15yr with the lowest interest rates I can get with a credit rating about 740- Yes I feel more comfortable getting stuff paid off quickly rather then having lots of 30yr loans-Build 20% equity with improvements prior to refinance-No more PMI !

So far I have always invested my own capital and felt comfortable with all my deals. 

As soon as you can comfortably do it or have it arranged, change the exterior door locks to provide you some safety.  

This can be redirected back to them in a heartbeat and is a common ploy to make landlords feel more comfortable renting to them.Keep in mind that it is illegal to discriminate based on source of income.

So if you're ok with that the next question is your "comfort zone".

I have an agent that I am comfortable with. 

Some will loan based in asset value or purchase price up to a percentage they are comfortable with.  

You can try to transition your 19 units to prop mgmt to see if you can get comfortable with that before taking the plunge on 67 units ( but at the same time make sure you are not losing the 48 unit deal if there is a risk) .