Remember, every step you take now is building towards a brighter future for your family.

New ground up development is always brighter and yield better profit with often less headache than fixers. 

If you plan to flip and sell I would definitely go with carpets in the bedrooms to make them appear brighter and keep cost low.

I also prefer a brighter look, so lighter paint shades etc...Best of luck!

If I have a dude that works odd hours but wants to see properties at 5 AM, and it's worth my time, I'll show him properties then (and I'll remember to bring my flashlight).

This happens in hallways in elevators according to the Owners that I work with on apartment buildings.Most new builds these days use carpet tiles that can be cleaning or easily pulled out and replaced.It might not hurt to take a UV flashlight, dim the lights, and see if you can locate any "accident" areas.If its not pet (or trash as mentioned above), it could be adjacent tenants.As far as making things smell better, they do make scent machines that hookup to your HVAC system and you get to pick the scent it diffuses. 

Grab a good flashlight with some extra batteries B.

When on-site, the inspector identified that there was a crawl space in the back of the house, acknowledged that there was only a small wooden board covering the crawl space, and yet did not go in, did not shine a flashlight around, did not even open it.

The picture's looking brighter now.... all while getting into real estate and flying an airplane.

Investing wisely helps create a brighter future for all involved!