we haven't signed anything yet and neither has our property manager signed anything with the tenants accept for screening their rental application and taking the application screening fee of $40 per adult.House we are planning on renting is a 4 bedroom 1954 house with 1 bath in Portland Oregon ( frankly 3 bedroom and 1 media room which opens via sliding door to the backyard but does have a closet).

I know I need a window in the room to make it legitimate and have thought of a few other possible issues (maybe I need a closet, an electric outlet, lights) but besides these things I am not sure what other issues building a room brings up.

Dresser drawers pulled out, closets mostly empty, no sheets or blankets on the beds, broken mirror laying on one bed.

If you're part of a couple, you might want that extra bedroom(s) to be not adjacent to your room, so maybe a legal bedroom in the basement or at least a master bath/huge closet between you and your roommies.Regarding rehab.

Realtors have gone in to assist (elderly) seller with property relocation from closets in order to look for access, but found the closet floors are all carpeted. 

It's not worth bothering when you can just keep shopping a little harder and find something that has a useless family room off to the side where you can convert that to a bedroom. by adding a wall and a closet.

One thing I will disagree with is I would recommend always checking in the cabinet of every sink and peak in every closet.

Study/Dining Flex w/ French glass doors + Large walk in closets.

Also the 2nd house has an addition built to be a closet for a bedroom that is held up by two metal support beams but it still slopes and feels as if you could break through the floor if you jump on it hard enough. 

However, it will always be limited by its size, its lack of good closet space, etc.One issue that is odd to me is that the electrical panel is on the wall in the kitchen.