@Dave FosterI was renting it for 1 year, now I want to demo and build new, then sell.

If you are re-wiring the house, you do not have to demo all the walls, just the cuts to run the wires.

Much like the demo or renovations at some of my properties, "just because I can do something, or know how to do something, doesn't means I *should* do it."

I had closing costs and demo costs.

Drywall: $20,000 - If you need to drywall everything new, then yes, otherwise, could be less.Flooring: $18,500 - ~2200sf laminate flooring labor and materials = $11,000 (excludes demo of any existing flooring)Windows: $17,000 - If 24 windows, then expect to pay $14k-$15k plus demo of existing plus any framing needed (edit sizes or fix bad framing)Bathrooms: $16,000 - for 3 bath full gut remodel, this is too light.

Was there demo that was needed, fees etc..?

Very tedious demo & repair work when dealing w/ plaster walls.

Expect some mistakes and redo's along the way to add to the time.Expect any government inspections to add to the time.If you can keep the same team all the way through by the time they get several units under their belts they may be able to go faster--providing they can get the materials.In my opinion, it's more intuitive to look at each unit as a separate job, vs demo all kitchens and tubs in X units as a job.They can still come and demo several units, just for me it's seems easier to keep the Tiger by the tail this way.If you buy all of the materials at once, you will have to guard them against theft and store them somewhere. 95 toilets going missing probably won't tank your budget, but it might tank you enthusiasm for a while.Make sure to budget for a dumpster if you need one, and porta-potties for the workers to keep them from using the ones in the units. 

I bought a small portfolio in November and the roof on one of the properties (a triplex) is swiss cheese and the 2nd floor unit is down to the studs due to a roach infestation (the seller did the demo after having it fumigated). 

Vs a demo + rebuild vs demo + replace with prefab (I see HD sells an approximately equivalent 10x12 or so shed for $4k).2.