Cost $7k.2) The central air conditioner and furnace are original.

Insulating was an option but there's so much pipe to insulate. plus my tenants use the laundry in the basement so I figured it was just easier to heat the air.

It's a seller's market.So keep that in mind because I've seen some really questionable decisions being made under the pressure of a 1031 deadline...

But maybe a career change (sooner rather than later) would make them happier sooner and take some of the pressure off. 

Just the presence of others tending to improve accountability.I wouldn't put pressure on a good worker by sending in a bean counter to reel in expenses.

This allows air inside the pipes and accelerates rusting.   

The plan is to live in it, flip it, try to house hack it with Air BnB then sell it with a hopeful profit months to a couple years down the road. 

Finding a property will add time, you don't want to feel pressured to buy.

For example, a cold water supply pipe above that vent might have warm moist bathroom air from the downstairs shower/bath migrate and condense on the cold surface causing a drip drop minor leak.

I have seen that for Floor coverings and wall air conditioners but other items could be in that category.