EX. Say yoy have a 3-node GG with Gunner, Theif, and Warrior. You start out with Yuna in Gunner. All you have to do is have her change into Theif, then Warrior, the you can change to her special sphere.
CommSphere areas important for Mascot
– Besaid
– Kilika
– Mi’ihen Highroad
– Macalania Woods (not sure)
– Zanarkand Ruins
For all other sections, you could most likely scrape by without viewing the CommSpheres and still receive Episode Complete.