Since you'd mentioned landscaping I assume you've taken all expenses into account (e.g. water/sewer, repairs, etc...)? 

any water penetration?

You may need a sump pump or drain for the water coming from the new furnace.

The answer to your question is hidden in your question...in plain sight.Have you run the numbers out, over the next 10 years, using both options?

HI BP, I'm looking for a contractor to help us solve water infiltration issues in our unfinished crawl space.

Make bunny suits, respirators, gloves, goggles part of the process and make sure there is running water for cleaning on site.

Here are the inputs:Purchase Price: $400-450K per propertyDownpayment + Closing Costs: $90-100K per propertyMortgage Payment: $2,000 - $2,200/month assuming $2K/year taxes and $1.5K/year insuranceTotal Monthly Rental Income renting out all the rooms (6 bedrooms x $700 rent per room on avg): $4,200Total Monthly Rental Income renting out all the top rooms (3 x 700) and renting the bottom unit to a family ($1,700): $3,800Total Net Rental Income Before Utilities/Maintenance/Reserves/Capex:  Low: $1,600, High: $2,000Utilities: ~$400 assuming that you pay for everything, internet, heat, electric, gas, water, storm drainageMaintenance/Reserves/Capex: $400 to have enough to cover any items that could need repair, maintenance, etc and accounting for age of house and more wear and tear Total Net Cash Flow Per Month: Low: $800/month High: $1,200/month, Middle: $1,000/monthAlso, I didn't include you adding any extra rental income for for adding utilities to rent/garage spots rent/etc, so these cash flow numbers are very conservative but realistic. 

I’m running into and issue, during inspection we found some water damage to a portion of the subfloor and joist under the kitchen sink.

I washed with vinegar or TSP until the water ran clear.  

See: https://www.cookcountyil.gov/content/just-housing-amendment-human-rights-ordinance- Schedule your free ComEd energy assessment and get free areators, insulation, smart power strips, water saving showheads, etc.