Welcome back!. I have been answering a few of your questions. I hope you find the answers useful.
I looked at the photo's, the room looks pretty good, Any wall paper edging will not look good in that situation, the white walls are best just as they are.
On these color match and decorating idea questions however it is by far the best to go to the home decorating retail stores and get idea's from there... from a distance it is very very easy to pick the wrong things and the wrong colors. You can end up with a very messed up look that way.Very slight differences in color can make a huge difference, sometimes even ruin a project. What looks good in a photo may actually look very bad to many people when they are in the room...Lighting has a huge effect. Fluorescent lighting can absolutely ruin the colors in a room, there are many different kinds of bulbs you can buy. some bulbs make blues look green, and reds look orange or pink. so that the room looks worse when the lights are on.The basic rule for rental property of all types is to paint the walls an off white color... and keep the accessories in simple and in pastel colors.. nothing extreme and not too much variety in the colors. And pay close attention to anything that looks dirty... all such areas must be cleaned up or replaced.If you stay with whites and off whites, and maybe an accessory or two that is match to the floor tile or bathub etc you will be best off. just 2 or 3 colors to a room, including the floor and wall coverings.Let me know what you think, we can go from there.Phil