2.Don't worry about WB. That's not your major concern. The flash should overcome most of the WB issue. Leave it in auto. If you shoot in RAW you can also adjust WB in post processing.
3. A single SB 700 may be insufficient to evenly light up a 10 people in a row. With a single SB 700 you'll have good lighting in the center and the ends of the rows will be much darker. See if you can use one of the windows as a light source. Light one side with natural light (assuming it's daytime) and the other with the SB 700. If using a window is not possible, you should consider renting or borrowing another Nikon flash (SB 700 to SB 910).
4. Remote the Nikon flashes using Nikon's Creative Lighting System (CLS). Either have stands or assistants point the flashe(s).
5. Practice, practice, practice before you do the shoot. Go over to the gym with your new camera and flash(s). Take test shots.
That should get you started.
"Red is gray and yellow white, but we decide which is right ....and which is an illusion"