My sense would be to bring it up to date and neutral  but that will depend on the market and location.

I think it at best it might be cashflow neutral sliding into slightly positive over time.

It only goes to a title/escrow company (or whatever neutral third party will be handling your escrow/closing), but never to a party directly involved in the sale. 

This was good and bad - yes, these upgrades/updates would likely have pushed my final sale price higher but the expense and time invested to complete them may have neutralized the benefit.

To this end, I have purchased cash flow neutral RE.

That being said, a neutral light fixture is $20.

I don’t know if you picked things you personally liked - I know with my 2 yr cap gains free tax play live in rehab I chose white cabinets and neutral grey paint throughout instead of personalizing anything in the house for ME

I want to paint all the walls a light neutral gray.

A lot of properties may be initially cashflow negative or neutral to start but rents do go up and you should be able to get your costs covered and then be positive after a couple or few years. 

Price increases have outpaced rent growth, and anything cash-flow neutral (after all expenses) is a win in my book.