The burgundy couch can definitely work! I'd go shopping for an inspiration area rug you LOVE that incorporates a bit of burgundy along with some light cream colors and lots of your teal and/or blue. It's OK, in fact it's preferred, for the rug to have some accent colors as well, such as orange, lime, bright yellow, whatever. The point is, you're relying on the rug designer to choose your palette for you. Since they make their living choosing colors and making things go together and look good, 90% of your color choices are made available to you right in the rug. More color would definitely help this space (although to be frank, I wouldn't necessarily hope for a lot of real mood uplift from this type of change).

Houzz has some great pictures where a darker couch like this is integrated into a coastal look.

Hi! I love that you want clean and happy, because that's what I love! And I completely agree that your home can be a mood setter for you and your family (which is why I love decorating)! Here are a few area rugs that may work for you:

http://deciture.com/shop/rugs/7/granada-area-rug-i/ (comes in a beautiful blue and green)

http://deciture.com/shop/rugs/7/spiral-mosaic-rug/

http://deciture.com/shop/rugs/7/starfish-area-rug/

I think khaki stools would look wonderful:

http://deciture.com/shop/furniture/7/custom-roll-back-counter-stool/