Do I need room treatments? floor plan included

If you are going to sit at the desk, use headphones.

You can take a decent $20,000 system but if you put it in a closet, it's gonna sound like crap.

Don't try to talk a Japanese audiophile into this concept. They pack Tannoy Westminsters and Klipschorns in tiny rooms with flea powered SET amps.They say living space is at a premium in Japan.I envision this setup as a giant pair of headphones!!If you browse the systems pages here on A'gon,you will see lots of members with lots of high end gear in tiny spaces.Personally,I don't get it.Oh well,to each his own.I realize Poolhut isn't talking major bucks and anyway,it's his gear and money,so he should do as he pleases.Pool,sorry,but I have no idea how to treat your room.I just felt like rambling this fine morning.Good luck in your endeavor.

IMHO - that room (if it's to scale), and your use of it and arrangement required because of your use, doesn't justify the expense of the equipment you are considering using. Use it in another room where it can work well.
You can take a decent $20,000 system but if you put it in a closet, it's gonna sound like crap. I'd go with a much smaller desktop-type system and put my money and efforts in another more workable room.
Just my two cents worth.
Good luck though.

If your listening sitting at the desk I'd think PROBALY not as you'll be VERY nearfield. Try to get the sub outa' that/any corner. Slide it up or over a bit to reduce bass issues.

Depends. Where are the chairs?

Not yet. First move the speakers to the long wall, then work from there. Also, need to get the speakers away from the wall.