Some kosher companies make cereals that are Kosher for Passover.

Chametz can be eaten in Jerusalem until the morning before Passover and cannot be eaten again until the end of the Passover season. The exact time until when chametz can be eaten is publicized locally in Jewish communities. Some religious Jews burn or destroy any chametz they have in preparation for Passover.

No, bulgar is chametz.

Chametz (Exodus ch.12) is leavening or leavened goods such as bread, cakes, and many other products. Torah-observant Jews do not eat them in Passover.

Perogie dough is made with raw flour and therefore is chametz. They cannot be eaten during Passover.