I don't know about Teppan Edo specifically, but you can split entrees at any a la carte table service restaurant (where you are charged based on what you order). At buffets, you are charged per person, regardless of how much or how little a person eats, so splitting entrees doesn't really apply there.
Yes, you can split entrees. The last time we were at Tappen Edo a couple at our table split. We split entrees at other restaurants all the time.
We also share entrees. My kids will often order off the adult menu and share vs getting 2 kids meals. The choices are better on the adult menu.
