Do you want this thing to be the tipping point for them to leave and you have turnover costs and a vacant unit? 

For 2 units; DSCR can go to 85% LTV or 15% down for purchase OR 75% LTV for Cash out in your scenario. 

Specifically from the Caged AC Unit into the attic (concrete slab so no crawl space).I was thinking of just building a tall vertical box to place this into.  

My advice is look for a good 2-4 unit investment property that my be a little outdated or need some TLC/renovations. 

Examples might include areas in the Midwest, Southeast, or Sunbelt regions.Multifamily Properties: Consider duplexes, triplexes, or small apartment buildings to increase unit count and spread risk across multiple tenants.Short-Term Rentals: If you’re comfortable with the management requirements, STRs in vacation or business travel markets can offer significantly higher cash flow potential than traditional rentals.Value-Add Properties: Look for opportunities to buy undervalued properties where you can force appreciation through renovations or better management.Decision FrameworkRun the Numbers: Compare the projected cash flow, equity growth, and tax implications of selling versus holding with a refinance or HELOC.

Either starting with a multi-unit or house hacking to mitigate the payment.

We signed the lease and the tenant moved in the unit in Nov.

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).

Beginning your real estate investing journey with a 2-4 unit property is a great way to get started.

If I had to guess I would say your money could “develop” 1-2 houses in Staten Island but in the right market you could easily get up to 12 or possibly more good units fully paid for.