So there is no need for a specific distribution of tenancy in the purchase of the replacements. 

The windows were recently replaced, but the trims are original.

I've done a search on BP and have read a number of threads strongly recommending replacement of knob and tube so I am familiar with the safety concerns.   

I've done a search on BP and have read a number of threads strongly recommending replacement of knob and tube so I am familiar with the safety concerns.

We replaced the windows, floors, new paint, new bathroom and several other updates throughout.

In July, the tenant purchased a $8500 new 3 ton AC unit to replace the already working unit (previous was a smaller size that he was unsatisfied with).

Take floors: My area it is $6 sf to replace.

They knew the monthly payment component wasn't reliable, so they purchased them, and unloaded them for the "cash profit today" option, as fast as possible, rather than the longer term "collect monthly payments" option (which, if there are going to be monthly payments, is generally more profitable [especially if they were ARMs that go up in interest rate & payment over time{1}], that's why everyone wants you to sign up for a monthly subscription for this or that).

Found a renter for 9600 sf building to replace industrial renter and build out a billiard club.

It makes more sense to just obtain a larger HELOC to replace the current one.