Create like a multi purpose use of the space so somebody can use that room as their living room and also their bedroom.

Your lease or statute may address this, but this is clearly endangering the lives of fellow tenants in the building, which is non-curable.

I need to take steps to make sure the apartment is as well maintained and upmost safe for anyone living there. 

I've noticed in some markets, there's an additional tax you have to pay on gross monthly income.

Would prefer to invest instead of own the home I live in.I've have had it suggested that to get started, I should buy a property that is under 100k in cash. 

I lived there myself for 4 years, then moved out and converted it to a super-profitable short-term rental (it's ideally situated near great restaurants/nightlife, the National Zoo, Rock Creek Park, and hotels that host professional conferences).

Just as a reminder in addition to the interest rate, amortization schedule and fixed period of the loan, inquire about: 1) Prepayment Penalties (In case you want to refinance in a few years), 2) Possibility of Rehab Funding, 3) Reserve Requirements, 4) Personal Guarantees, 4) Rate Adjustments (i.e. at the 5 year mark) to understand other variables in the loan product that works best for your project.

In this ever changing world we live in, property management and business owners must adapt and change on a regular basis to keep up.

In addition, you are also required to materially participate in each property or group the activities. 

Additionally, they may want to seek legal or financial advice to ensure they make the best decision for their specific circumstances.If after all this if you still looking to take advantage of such opportunity, I would verbalize in your new duty station that you invest in real-estate and that are looking to take over a loan.