I put a new roof on the house with a tenant occupied recently.

Lastly, any new home builders and/or modular home builders in NJ who would be interested in a project like this?    

Project management, SCRUM, additional users would be amazing but a secondary requirement. 

I talked to a structural engineer and he recommended removal of the roof and sheathing, correct or replace the trusses, and re-roof.

I would certainly rely on a real estate agent to pull true comparable rentals in the area (as opposed to any kind of "Zestimate") to know what your projected rents might be.

I’m buying a 3 bedroom 1 bath single family home... it has a new steel roof but needs windows.

The roof is newer, as in within the last 5-10 years, and has vinyl siding on the outside, and no visible structural damage. the units are very clean and ready for tenants to move in.

It'll now need a new roof and one exterior wall was severely damage.

-Projected monthly rent = $1,300-I calculated 5% for cap ex, property maintenance, vacancy, and $95 a month for property management.

I only have to do another 640 million in annual sales here locally to over take them :)  Anyway I am closing on a 90 lot project beginning of December and if we can keep the velocity going that should move me up into the top 20..