Demo all the drywall out, remediate mold, complete reshingle of roof, replace all windows, replace all outside soffit/fascia/dormers, replace all siding, repipe whole house, rewire whole house, redo all mechanicals such as hvac, redo all interior and exterior doors, paint interior and exterior, replace any framing or insulation damaged by mold/water leaks, replace all gutters, minor landscaping, minor outside repair of concrete wall, install all new cabinets, install all new countertops, replace everything in 6 kitchens, replace everything in 6 bathrooms, install handrails,  install significant flooring and minor subfloor repairs, and install all trim in house.Project will cost around 150,000$.What would be fair for this?

The kitchen area flooded  anytime somebody used a bathtub. 

We were not impressed until we came across a contract sitting on the swollen formica kitchen countertop that the former owners signed which basically read that whoever became the new owner would inherit $67k dollars worth of free renovations.We got impact and sound insulated windows and doors, a NEW AC unit and AC ducts, insulation in the attic, they increased the amps to the electrical.

Put new knobs on the kitchen cabinets, and replaced some broken soffit pieces and window sills that had rotted out.

The best are chapters of NREIA, National REIA.FYI;  most old timer experts, experienced investors are in the local REIAs.  

Here are additional things to consider: 1) units that are below market rate 2) minor value add purchases that are short of requiring tenant to vacate for 30 days (most LL I have been communicating with believe that a significant kitchen remodel may be necessary to terminate lease due to a value add). 3) (this is the one that I find most impactful) Tenant termination is now limited to a few items such as uncorrected lease violations or rehabs significant enough that they mandate more than a month of vacancy. 

Duplex - 2/1 both sidesPurchase: $97K all cash no and includes realtors work for finding the dealRehab: $20K (floors, kitchen/bathroom, paint and other cosmetics)ARV: $135K (will then refinance at $101K leaving roughly $16K in the deal)Rent: $800 each $1600 total (current tenants on month-to-month at $500 on both sides)Vacancy: 10% ($160), CAPEX: 8% ($128), Property Mgmt: 10% ($160)Mortgage: $376, Taxes: $150, Insurance: $100Lawn Care: $100, Septic: $13Cash Flow: $413, CoC: 30.9%Property is in a very stable C Class neighborhood.

I probably got every kitchen appliance you need.

They will often waive that for an investor they regularly fund but probably not a first timer.

During this time rates were at an all time low!