What is the legitimate Sharia position on holding a party to celebrate my daughter completing her first year and to bid farewell to my apartment, knowing that I have not called it a birthday celebration and will not repeat it annually?

There is no harm in celebrating a daughter's first birthday and bidding farewell to an apartment, as long as it is not repeated or taken as an Eid (festival), and it does not fall on her actual birthday. Such celebrations are permissible joyful occasions. Jurists have permitted celebrating joyous worldly occasions, such as the return of a traveler, building a house, or a woman emerging from postpartum confinement. Similarly, feasts for joyous occasions like the wedding feast, the feast upon a woman's emergence from postpartum confinement, the circumcision feast, the housewarming feast, and also graduation parties or welcome-back parties from travel are permissible. This is because their intention is not worship, but rather a manifestation of joy for Allah's blessings. The prohibited aspect in this regard is the creation of a recurring Eid.