I typically look at properties in the opposite orientation and it seems to me as though many here do as well. So, as a wise man said, you begin with the end in mind.
5 units, cash flow goal is $100 per unit (a door). That might be a little high for the Gar apt and a little low for the 3-bed but you gotta start somewhere and we always start at a minimum cash flow of $100/unit.
Looked at that way, you need $500 cash flow... which makes your costs
$977 enumerated above
$500 cash flow
$1477 monthly requirements before mortgage.
I allow 5% vacancy based on a decade of history, multi's often use 10% so $1765x90%= $1588.50 revenue
Revenue is now $1507.50, minus costs including profit @ $1477, which suggests you can afford a mortgage of $111.50. That's probably not happening so you get to keep asking questions... do I want to count the management fee as profit? Can I raise the rents? Are there deferred maintenance issues?
For our model, I'm not seeing the opportunity here, especially at the suggested price of $80,000.