It still needs paint, carpet, new toilets, attic insulation, new upstairs heat pump, and the downstairs still needs to be cleaned and painted.

Alternately if the lease is long enough you could buy it and then resell it in the future – although leasehold buildings typically do not increase in value, a long lease normally insulates the depreciation.Just some things to note from a lending side for leasehold buildings, condotels (like the Executive Center, Ilikai Apt Building), and investment properties; please bear with me if you know this already and its already been mentioned in this post: -Any loan you get for a leasehold building will need to have a 5 year cushion built in before the end of the lease. 

If it is siding, insulation, etc.?

And they are insulated from the broader economy.  

Is there a good method of sound insulation between floor joists?

Even though I have budgeted for a reserve, as all new systems (plumbing/heating/electrical/insulation/) have gone into the place, the only thing I know I'll need to put funds aside for is a new roof in about 10 years. 

My only concern short term is that I am insulated enough with equity, cash reserves, and cash flow that I can weather any short term storms without being forced to sell ... other than that, it is in the noise so far as I'm concerned.As for commercial property, yes asset values are tied to NOI, so you have the opportunity to more directly force appreciation by raising rents and/or reducing expenses.

We are planning to renovate the living room ceiling and attic space above (repair the cause of the leak and replace any insulation which has been wet.) while the tenants are on vacation visiting family this summer.

Don't forget remove all insulation and re-install.

If it was just insulation, Sheetrock, paint, trim, doors, floors, kitchen, baths, and then finish it out, $60k should cover it.