Issues of Leaven Disqualifying the Pesach Offering
The illegal possession of Leaven during Slaughtering refers to the Leaven of the Slaughterer, the sprinkler of the Blood, or any of the members of the Offering: Pesachim 63a-b
The Kohen who Burns the Fat on the Altar is in violation of the prohibition against having leaven, if one of the group possesses Leaven: Pesachim 63b-64a
Whether the Leaven must be in the external room of the Temple for violation or not: Pesachim 63b
If one possessed Leaven during the Slaughtering of the Offering as a Pesach Offering: Pesachim 63a
Above case, but he slaughtered it with another Offering intended: Pesachim 63a
If one possessed Leaven while Slaughtering the Pesach during the holiday of Pesach, with or without intent to use that Offering as his Pesach Offering: Pesachim 63a, 64a