Would I go to the current owners bank to see if they would allow a subject to loan? 

It’s time to look into home owners/rental insurance.

you fixed everything the previous owner neglected, you have good tenants, your rents have gone up, etc. for example, my cash flow ranges from: $0 a month on my class A property, to $300 on a single family that I BRRRR'd and have a 4.5% interest rate on. 

Many employers are seeing now as a great time to opportunistically buy or lease, usually downsizing, into new office spaces in the district during this period where there are still depressed prices, even on some Class A office spaces.The Resurgence of the Office Market in D.C.The resurgence of employers returning to the city with the pandemic fears now in the rearview mirror is apparent with Q4 of 2024 being the first quarter of positive leasing absorption for office space in the District over the last 10 quarters (Source) Another example is Boston Properties Group (NYSE: BXP), the largest publicly traded developer, owner, and manager of Class A Office space in the United States, is building a 320,000 square foot new trophy office in Downtown DC, with 5 floors already pre-leased to the global law firm McDermott Will & Emery as well as the Rockefeller Group developing a 422,000 square foot office building slated for delivery in 2026 at 600 Fifth St.NW, which is similarly 50% pre-leased (Source).

A SFH in a neighborhood with HOA or owner occupant neighborhoods your rental property can stand out in a negative way because tenants don't waste their money watering the yard. 5.  

With current interest rates, and they are at least 1% higher with potentially additional points for non owner occupied property, it is hard to find properties that will allow for positive cash flow after paying the mortgage, if you are looking for money for the down payment from a private lender, those are normally at higher than market and I am not sure it would be possible to pay it off.... please remember you need to take into account that you may not have a tenant for a certain amount of time, a tenant may stop paying rent, or you will have a big ticket item to fix, so I would wait if I were you and save to have enough for the down payment and closing costs and perhaps some money set aside for repairs. you also want to make sure that you have your own emergency fund outside of the money needed for the investment property because life happens ....

If you are going to be an owner-occupant, want a low down payment, and are planning to do a renovation, the FHA 203k and Fannie May Homestyle loans are your best optionsHow do you know the property is currently upside down on the mortgage? 

Unfortunately, the previous owners used the same lease for this garage space as they used for the residential units. 

While I have a fantastic rate, the co-owner's giving me the option to refinance or he'll force a sale.

If a property goes into foreclosure on a second, as Ken said you will either be buying it subject to the first mortgage - meaning it's your mortgage now - or the first has to be satisfied to take possession of the property - or the owner of the first is going to be there bidding what they are owed, so you would need to outbid them to get the property and then you are the person paying off the first mortgage.