Thanks.Mold usually requires a warm, moist environment to grow.

That helped, but, this being South Carolina, it is still to moist.   

Tenants aren't going to open windows to let the moist air out.

the darker the stain/finish, the more it would protect the wood since it has more pigment in it.i have used Readyseal from texas many, many times and have been super happy with it. they ship and it's cheap/quality stuff.also, painting/pressure washing forums have many threads about the best stain/sealer. no matter which one you use, you'd have to restain every 2-3 yrs.i'd skip all that and get composite. looks much better.post pics when u are done.

Instruct them to air out the bathroom after treatment, and to try and prevent creating a moist environment.

(green toes, green lawnger, etc) These are pigments and paints.We tried to establish Buffalo grass here, looks like we have to much annual rainfall for it.I Personally  have a 2 acre lawn, on top of the Hill we call a mountain. (1000 ft above sea level) I have drip irrigation that feeds he flower beds.

The cooler basement temperature would act as a dehumidifier, so I'd guess the walls would get fairly moist. 

The insulation held the water seepage in & kept the joist & the subfloor constantly moist for a very long time. 

I am hoping that if I pull of the paneling I will be able to see any potential leaks or drafts that might be pulling in moist air.

The bit coming into our unit seems to have stopped but the wall is still moist and harboring mold.