About 50% occupied.

I’m thinking an FHA or conventional, ideally owner-occupied.

Thats just incorrect if its owner occupied.

I’ve considered mid and short term rentals, but from what I’ve seen, Baltimore city unfortunately does not allow new short term rentals unless the property is owner occupied. 

Duplex fully occupied with rents of $2,500.

However, every company I find either doesn't insure non-owner occupied units or is extremely expensive.

nice, house hacking or are you occupying both units?

@Jason Wray who's doing 5% down on owner-occupied 3-4 units?

Quote from @Jaycee Greene: If you go the conventional/DSCR route, these are considered "Commercial" loans and the properties are referred to as "Non Owner-Occupied" and, as such, the cash flow of the property is most important, and your DTI is not generally included in the underwriting.

For example in many jurisdictions I can STR units in a duplex but cannot STR an ADU (some jurisdictions will let you STR if you owner occupy).