According to the inspection, a replacement job must be completed on the roof, windows, doors, siding, soffits, back deck, and front porch, to name a few (which one should I even start with?).

Even if, say, the roof needs replaced, but it isn't currently leaking and keeping you from renting the unit, then you can punt that option, at least for a bit.And I also second Rob's take on going straight to the contractors.  

Its a 3 unit row-house built 1900, pretty good condition, newer roof and water heaters, not sure of other stuff.

We believe the property could have been appraised for ~$115k (new medal roof, new HVAC, floors, fixtures, new sheet rock throughout).

Multi family is through the roof, as I'm sure it is in your area as well.

The building has been extensively renovated by the prior owners in 2022 including new heat/ac, appliances, flooring, kitchens/bathrooms, roof.

A contractor can help yes when it comes to looking at it and telling you how much or what you be looking at if you want to upgrade or fix something visible but you need the inspector to check out the roof AC and plumbing thoroughly despite what it looks like in person I’ve seen mini jacked up ceilings.

If you are working on roofs in bad weather you might long for a way out and becoming solid financially is the way to do it.

Everything passed except for the "secondary roof" which consists of a membrane roof over an unheated, patio "room" separated from the man house by glass sliders.

For a lump sum, I would have 20-25k set aside as a just in case. 10-15k is ok, but if a furnace breaks and you need a new roof, that is done and over.Basically, have as much as you can, and never below 10k.