If nothing else, the silver lining I see is some time to get caught up on things we normally don't have time for; workouts at home or in a park, spring cleaning, or learning something new like a skill or language.

I do not know if Auction.com is still owned by many of the major banks, but it used to be and that was how they cleaned out their REO properties en mass!

So this is a possibility, but clean solutions are always the best.

New carpet, electrical and plumbing in the basement.

Again, this has the benefit of keeping a clean, separate set of books for this deal, especially if you plan on doing more and with the different set of investors.If you run everything out of your single member LLC, it will get too messy if anybody gets "upset" even if you keep a separate set of books and bank account. 

Well I was just down the street at the house talking to someone who was cleaning up the yard.

The contractor suggests duct cleaning that we'll do anyway, but I was wondering if anyone has had a similar issue like ours and could provide additional info on the questions below:- some additional info re reason of the smell (what kind of bacteria is it?)

I even asked several tenants to move out since they don't keep apartments very clean. 

Then, if needed, send in a cleaning crew before allowing new people to move in. 

Wait until the current tenants leave, then you can clean it and show it.I normally show occupied rentals but we need to follow the rules and play the game, even if it costs us a little.