House flippers, restoration companies, relatives, and land lords all deal with homes that have been trashed out.
NTS does not perform trash removal but do treat the odors after all the trash is gone. If this is your situation get the property to an empty status. Contact NTS and have them perform an inspection and give you an estimate for cleaning.
Once NTS has gone through the home and conducted it’s services the owner will then be able to renovate the property. If you know there are going to be parts of the home which will be replaced, do that first. There is no need spending money on a subfloor with odors if it is going to come out any way.