Since you got a great deal on the house hire a fire restoration company
to do just the gross cleaning.

Toss all carpets and everything else fabric that will hold the odor.

clean everything by scrubbing with bleach water, dry completelt.

then paint all surfaces with BIN or KILZ primer sealer, and all real
wood surfaces with OUTDOOR POLYURETHANE, although you will have to sand
all floors at least a little so the polyurethane sticks good.

you will also need to have the furnaces and ductwork cleaned and
deodorized treated.

if you fail to do ANY of this the stench will reappear, espically at
warm moist times.

essentially you cant clean the odor away, you MUST seal it into the
surfaces so you dont smell it

I had a similiar home restoration twice, once with a fire and once with
human odors. it can be done but I wouldnt live there till its cleaned
up, so you dont get ill.

fire restoration sends peple in moon suits with full respirators or
this reason.

you can do the entire job yourself but getting the worst out first
professionally will still save you tons