Certainly #2 would be best. I'm not quite sure why people have a conception of windows behind monitors being a bad thing. If anything, it could be possibly good for acoustics as some low end resonance could escape through there. Windows are a hard surface, so they certainly reflect. However, walls are also hard surfaces, and will reflect similarly. So whether you need to treat a window or a wall, you would treat it similarly..
You would definitely want to be positioned against the window in that room since your closet is on the opposing side as well as the entry way. This will give you the best symmetry possible in your room.
I would advise putting your monitors all the way against the wall, and pulling them out 6" at a time to find the best spot for them. The 38% rule, as stated above, can help in large rooms, but in most small rooms we've found that monitors all the way against the wall typically gives the best response. SBIR is the culprit that makes being some distance from boundaries a problem. In a large room, 38% is a good distance from any boundary but in a small room puts the listener at about 50% of the room length which is the worst spot you could possibly be in. Also, the farther the distance from a wall you are, the lower in frequency SBIR is. If you're a good 2-3 meters from the front wall, SBIR will likely be low enough in frequency that it won't cause any inherent problems. However, one or two feet away from the front wall can cause some major peaks and nulls due to SBIR. You can read more about positioning and SBIR on our Education section of our website here: gikacoustics.com/education.html
