I would like to give it a test run before I dive head first and kind of have that safety net to fall into of it being my primary residence if things went not as planned.

Im seeing things like 7 year ARM with 25 Am.

There are also rules you need to understand about keeping all investment activities at arm's length and avoiding any self-dealing or dealing with close family. 

Downfall is they are usually set up on a Fixed ARM- interest only for 5/7/10 years. 

Sellers can presently get away with this crap because the multitudes are clamoring to chase prices, driven by FOMO, armed with low interest rates, and willing to accept bidding against those down the road projections. 

You have issues with potentially co-mingling (the mortgage payments should be coming from your bank account not the entity's), alter-ego (one of the threads show my logic how this would never happen on an arm's length transaction), Title Insurance Policy, etc.I'd be happy to chat if you like. 

e.g. growth, safety, taxes, regulations, etc.

If I were in your shoes, unless it posed an issue to safety or looked horrible I wouldn't touch it.

You said mold is growing, which is a clear health and safety issue.

I would love a 30 yr fixed under 5%, but I anticipate given the current environment I'll get something more like a 5-10 yr arm amortized over 20 yrs.