I wouldn't advertise it as a bedroom and would make it clear that it is not to ever be a bedroom, but am concerned about the presence of an unpermitted room in general, but I may be overreacting. 

The VRBO guest left a 5-star rating, and on Airbnb, I have one 5-star rating with another on the way.However, I've noticed something that has raised some concerns, and I'm not sure if it's specific to VRBO or related to my listing.

That should be your buyer's concern and insurable title is "good and merchantable title". :)

Within 5 minutes I got a message from him stating that underwriting has concerns about the location of the property being rural and not having enough sales comps. 

My concern is that even if I don't file a claim, my insurance premium will still increase dramatically next year because of my neighborhood's claims.

I am also concerned because my goal doesn’t create any money (there isn’t any money that building this house will make). 

Solve maintenance concerns and you will have happy tenants.

I am curious how the current leadership will manage the lands, development, etc. and have some genuine concerns.

I'm concerned that if I install a separate meter will that cause a reclassification of the property from SFH to duplex.

There's a lot of large apartment building going on but I'm concerned that there may be too much building given the number of jobs in the area.