Is this West Elm sofa the kind of thing you are looking for? Or even lower to the ground? http://www.westelm.com/products/4227534/?catalogId=52&bnrid=3918508&cm_ven=Google_PLA&cm_cat=furniture&cm_pla=Sofas_+_Sectionals&cm_ite=West_Elm_Baxter_Sectional_Sofa_Cotton-Rayon_Ikat_Print_Feather&adtype=placi_src=17588969&ci_sku=4227534&ci_kw=%7Bkeyword%7D

based on the drawing, the wall where the bed is. HOWEVER, you mentioned that this drawing is not a true depiction of the furniture you will use and the wallpaper. if that is the case, i think the wall paper can work on either wall, it all depends on how busy this wallpaper is and how "plain" the bed is. if you go with a busy wallpaper behind the bed, you may want to keep your bed and bedding on the minimal side so that there is a good visual balance to the overall composition. if you go with snazzier bedroom furniture, then a busy wallpaper may be a bit much and you may want to put it on the other wall or use a textural option to serve as the bed's background rather then another focal point.

That is a really small space,I think maybe an apartment size sofa would help you get the look you need and a smaller table or even removing the table and using two bar stools

The market is full of tropical/botanical art at the moment which lend themselves well to tropical or beachy looks. The look you are after calls for natural textures with a soft colour palette, think linen bedding and layer it up with throws and cushions for texture and pops of colour. In my opinion drapes are not a good option in your room as the ceiling slopes to just above your window at a certain point. This would dictate the height at which your drapes hang and, in this instance would be too low. To soften the windows, I would have a tall palm or Fiddle Leaf Fig tree in wicker basket. It also looks like you have the space for a chair.