If a Sephardic orders a piece of meat/fish in a restaurant and by accident forgot to tell the rabbi to put the food on the grill, is it asur to eat it Bc of bishul akum?

Can a sefardi go to a hibachi restaurant where the goy cooks everything in front of you and just the mashgiach put on a fire?

If one accidentally bought food at a restaurant that he learned wasn’t kosher can he give the food to a goy