You are right..that it is different for everyone. It is also different for many on different days...some days I can eat fried food..some days none at all. If I eat fried foods it has to be fresh oil, done at a high heat so the food is crisp and not oily.
As for seafood...i eat it all....broiled, baked, grilled, fried and raw. I love sushimi and many sushi dishes. I also enjoy raw clams and oysters. Fish, shrimp, crab, mussels and clams....all very good and I eat some kind of seafood at least 3 times a week
I will admit that recently the safest thing for me is to eat a moderate amount of sushi..or to eat a nice white flaky fish that has been baked, broiled or grilled with just a light amount of butter, salt, pepper, and lime juice. It seems to settle very well with no major stomach issues. of course the fried okra, nassau grits and key lime pie put me over the edge.