Yes, you will need a ticket to enter the park where the restaurant is located. There are other hibachi type restaurants in the orlando area that wouldn't require theme park admission.
Any restaurant in any Disney park must have a park ticket to get in. Sometimes you can get a conference ticket for later hours only, but still, need a ticket.
Yes, this restaurant is part of the World Showcase at Epcot
As others have mentioned, yes, a ticket to Epcot is required. If you are still wanting something around this area, I would recommend checking the restaurants in Disney Springs, which does not require a ticket for admission. I particularly enjoyed Marimoto Asia (though this is not a tepanyaki style restaurant).
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