I hate doing tile so I'd do LVP on the floor and hire out any backsplash or surround and the vanity granite or marble or whatever you're using on that.  

Fully gutted the house, Opened up the wall between the kitchen and living room, New cabinets, new granite, new appliances, new windows.

Granite counter tops or marble or quartz?

We also use it on windows (no streaks like windex) & granite etc.I use well dissolved TSP in the Rug Dr for bad stains esp the stairs but the Deca Clean product is fantastic if you ca get it.

I started with a property that needed mainly cosmetic fixes -- new granite, knobs, paint, floors, etc.

Probably not the greatest idea.Other house put 12"x12" (cut to fit) granite tiles on top of old tiles, they now have a good slope so water does not sit below window.Both are just band aides, if you gut it then just pull window out, glass blocks sounds good too.

For example some people want wood floors and granite counters in their personal residence, but may not want that in their investment property, if that makes sense.As @Mark R mentioned, we don't have a lot of duplexes here, like other parts of the country. 

My initial thoughts are to spend money upgrading the kitchen and master bath; granite countertops, tile backsplash, maybe a pot filler over range, tile shower, extra windows?

Rents for a beautiful student property on Court can be $800-$1050/bed, where middle-condition properties on the West Side (meaning, clean pretty kitchens without granite countertops) will rent for $550-625/bed.

Featuring a renovated white kitchen adorned with granite countertops and stainless steel appliances, as well as new hardwood floors and upgraded baths, this property is truly exceptional.