odor can be elkminated 100%:)
you do what the fire restoration industry does.
remove ALL carpeting and padding!!!
discard, its not worth the hassle and cost to clean, plus it shrinks if you send it out, for power washing at a speciality carpet cleaner. just toss it all, get the color and style you want.
scrub all walls, floors etc.
lightly sand floors, then coat with OUTDOOR POLYURETHANE, multiple coats. it doesnt have to look good, urine stained areas on hardwood will be black, but if your covering with carpet it doesnt matter.
paint all walls with BIN or KILZ primer sealer. 2 coats, then regular paint.
you cant remove urine and pet odor or even tobacco smoke stench.
all you can do is seal it in so you cant smell it anymore.
done like this the odor will NEVER RETURN:)
any attempted scrubbing or other odor masking will come back every time the weather is moist:(
this is what fre restoration companies do after home fires, another hard to remove odor.
tell the sellers you must have a discount to cover this cost.
been there done all this, its not hard just grunt work