Sushi and the DDP

[CoolPool]

Myself and two 7 year olds will be on the DDP. We ALL love sushi and sashimi. So my question is where can we successfully get sushi/sashimi on the DDP. Complicating matters is that none of us eat shellfish. I have read menus but it is confusing as to what would be included and what is not included in restaurants. For example, I would love to go to one of the Japan EPCOT restaurants, but it seems like the options are heavy on shellfish or its offered independently of the DDP as appetizers? Am I reading the menu correctly? Can I make substitutions like salmon or tuna or another fish instead of shrimp or crab?

I suppose I have one other question...can we decide when we are there to upgrade to the Deluxe Plan if it seems our eating and our needs are not compatible?

Thanks dolls!