I think you should get a curved tv which would fit the space in the back and then get bean bags like fatboy or something similar. Would be really chill!! Also I would carpet the whole floor so its comfortable up there!! Good Luck!
Since you are planning going with a triple monitor and you have no space for the KRK’s, I would recommend the Bose companion 5 or the cheaper companion 2. I personally own the companion 5’s and they are absolutely amazing. You will never regret the purchase although that could be said for any Bose product. Excited to the see the changes!! :))