Bathroom includes a ceramic tile floor, shower and single vanity.

You can not install key locks on bedroom doors.In Jersey Heights, the rent of old building  is around $1600/month for a 2 bedroom apartment, around $1800 for 3 bedroom 1 bathroom apartment.

Compare: how nice the kitchens & bathrooms are.

We mainly work on bathrooms and kitchens and restore what the restoration companies tear up when they mitigate water damage.

Wondering if there is a basic formula out there for estimating rehabs (e.g. bathroom rehab generally cost ??

Try looking into zillow/Redfin and see what your potential rents you can get near the neighborhood by filtering the bedrooms/bathrooms of the intentional property that you are planning to buy.

What happened in the bathroom remodel?

My wife had already remodeled the kitchen, and after we got married, we spent some time to clean it up and do a full bathroom remodel. 

On entering the bathroom, I discovered the powder, and the odor, were INCHES of talcum powder on the floor where this person apparently "bathed" with the talcum powder, then carried/spread it throughout the apartment.

So that would sleep 8, and the master would sleep 2, so a total of 10 people using only 1 bathroom?