The black button is to call the office. It’s an intercom. You could get a heavy duty extension cord and run cord over the door in case you don’t look for outlet upfront.
I have a suggestion for your rows of desks/chairs - you can take a desk away from the rows that are next to the bulletin board and add them to the rows in the back. This way, the rows that aren't directly next to a bulletin board will be against a wall while desks that are directly next to a bulletin board will have a desk-wide space between the board and desk. I think this would clear up some space in the center walkway and you wouldn't have as many kids blocking the view for the ones in the back. I hope this makes sense! I know you don't want to block the classroom library, but I still think you would have enough space for students to access it at anytime. Great work so far! I am going into my first year as a high school teacher myself.
I usually don’t encourage new teachers to spend their own money, but you may want to consider redoing your boards with the Better Than Paper. It’s much more durable than wrapping paper and will probably not tear. And if it’s cut carefully, you may not need border. Perhaps those eucalyptus strands at the top that are so popular now. I’ve been in small rooms before and it is so frustrating. I love your philosophy of making a fun and comfy environment for your students. Hang in there, you’ll figure it out.
What if you moved the the short cabinets in the back, you have them locked. Then get rid of the big cabinet. move the wooden bookcases up front. and then just be done. The big air thing, needs to go in the back, trip hazard. Good Luck!
According to the 1st amendment, You don’t really need a US flag for the classroom. Also, you could just plug in the air purifier in the back extension cable.