There’s even two front entrances.

but they are saying because it has two separate entrances and a wall between the units it has to be treated this way. 

But when I try to find real estate groups out here they all charge you an entrance fee.

If yes, I've created an exhaustive checklist in irder to 'reverse engineer' the property, debt and title.After determining that the opportunity has merit, you need an entrance (and exit) strategy.If you are trying to buy the asset (the property) then you need to find someone who has the ability to pass title to you, either owner or the person in charge of their estate, if deceased (or conservatorship, if owner has diminished capacity). 

As we were going over our rehab plan we noticed the side entrance to the house has a landing that is lower than the upper level (1st floor) and goes to the basement. 

There is a seperate entrance to casita and it has no direct access or entry point into the house.

Assuming the basement has a private entrance, I'd say you've created a duplex.

Go to Home Depot and post on their board ask if you can leave flyers or a large print ad near the entrance/exits or hand out flyers to contractors, roofers, etc.Maybe your numbers (ARV, repair costs) need to be adjusted?

But they do not have onsite management or security gate at entrance.

There would be two main entrances into the building, and the tenant would have to walk to their apartment from there (so no exterior door to each individual unit).