Below is some info I just received from feng shui consultant friend.  Should be fun to use and implement as we layout the space.

Hello Robin.
Intuitively my first concern is the air quality for your employees. Do make sure you invest in some free standing air filters to help out the no window situation. The majority of the workspace is in the NW Helpful People and Travel Area. The elements for this area are metals. Water elements can also be used here. Gold, silver, white, gray, bronze are all positive. Blues, blacks, and water elements are also ok here. The Northern side of the workspace is the Career area. This is where you may want to put mirrors, water elements (fountains to water landscape art), circular items, and any career mottos or goals. You can use the colors mentioned above as well here. A large mirror can help to bring "light" in around the space. The Southern side of your space in the show room will benefit from more greens and slight reds. This is the Fame and Reputation area. You will want to highlight colorful images of your work on the walls. Live plants to silk trees in corners, on desks, etc will help to make this area come "alive". I feel you can go crazy with live plants here because plants help to absorb toxins in the air. The furniture layout is actually fine.

I would google Nasa's air cleaning plants to get a good list. Pothos is an easy indoor plant that doesn't need a lot of light to grow. It's also a rounded leaf plant that brings in abundance. It's a great desk plant and toxin absorbing plant. I feel you have a good intention for the space. It will not need too much work. Just make sure to keep it light and airy in colors. You can keep a fountain in the North work room and even one on the East side of the rooms. This will help everyone to feel at peace. If they can't see nature then bring it in.