What is the source and significance of stealing the אפיקומן?
It comes from Yackov stealing the ברכות from Eisav. It has a whole other level we tell the חכם a Halacha that אין מפטירין אחר הפסח אפיקומן why this Halacha? The answer illustrates the connection between Birchas Yitzchak and Pesach once more it was this Halacha that Yackov used when stealing the ברכות when Yackov brought the Meat from Korban Pesach Yitzchak was no longer able to eat because אין מפטירין אחר הפסח. We know that Yitzchak told Eisav “Go Prepare me food so I can eat and Bench You” .This means now that Yitzchak cant eat Eisav’s food he cant give him a ברכה..Then too throw in one last connection from Rabbi Yosef Chaim Sonnenfeld When Eisav came in and asked for his ברכה his father told him בא אחיך במרמה ויקח את ברכתך and if you calculate the Gematriah of במרמה it is exactly אפיקומן