Most of these guys out there want to do "cost plus" contracts so that you're responsible for all the labor and material costs and they just tack on their 18 to 20% on top. 

Do you plan on project managing/picking up materials/etc or hiring a GC/PM to do it all?

They charge what plumbers charge for labor and material to replace plumbing.

Hadn't really considered other building structures/materials, so will need to do some research on cost for materials that still align with the vision, look, and feel.

I utilized (and maxed out) my credit cards to afford the materials necessary to renovate the apartments (I know bad move) therefore I cannot acquire a loan of any sort to fund the initial funds necessary to acquire a hard money or DSCR or rehab loan.

Curious where everyone sources their material for flips/brrrs? 

Factory built with its potential for less material waste was attractive.

There is also I think the 500 hr material participation requirement for the $25k PAL to take that onto your1040. 

How much would it cost for material and labor for a 985 square-foot house?

The contractor is required to provide a 1 year warranty on labor and materials but replacement contractors are difficult to find because they have to warranty all the work ... even from the OG contractor.