Beyond that, on the street-facing wall, there is a flex room that I would use as a den/office space, but could also be used as a formal dining room.

@Adam K. yes I can see now that not all the bedrooms have windows, I wonder if you could convert the dining rooms (with windows) into bedrooms. 

There's a picture window off of dining room which I hope to change to doors that lead to a deck- the views are beautiful and there's a large back yard.

Most of the times there are rooms in a dining area or kitchen area to add a bathroom.

Removal of non-load bearing wall to open up to dining area.

We have that in the living/dining room of one of our places - I love it, it looks like wood but is basically indestructible, very easy to clean.Not sure what brand we have as it was already there when we bought, but I was looking at the Vesdura vinyl planks for when we need to replace flooring in the couple of units that still have carpet.

Having some home renovation done consisting of widening the opening at dining room and living room.

I feel like it doesn't matter who's TV/couch/dining room table is in the common area, as long as it's in a common area all tenants should have EQUAL rights to said furniture. 

Coordinating bookings, responding to inquiries about the properties (even the many people who don't end up booking), answering  questions about recommendations for dining, sights to see, etc, answering questions from the people who don't read the welcome email, answering phone calls, turning down negotiation attempts, rating guests and responding to reviews, maintaining listings and calendars, coordinating cleaning and maintenance, filing taxes, filing for permits, advertising, talking the owner down from the ledge when they get nervous about something ;), sending reporting to the owner, etc.

Staging the living room , dining room and the master bedroom will give a house a less stark feel and define the spaces for less time effort and money.