Can the expiatory fasting be completed after performing the Hajj, or must it be completed before Hajj if the fasting period extends until the time of Hajj?

You are allowed to break your fast on Eid day and during the Days of Tashreeq (the eleventh, twelfth, and thirteenth of Dhu al-Hijjah). Breaking the fast on these days does not interrupt the continuous fasting of the expiation, according to the preponderant opinion. As for the remaining days of Hajj, it is not permissible to break the fast on them; otherwise, the continuity would be broken, and you would have to start over.