Concerning the Ketoris, the halacha says that if one forgets on spice then he is chayav misa. There is a machlokes between The Rema and the Beis Yosef if that applies to speaking. The Rema says that due to tirdas hazman, people might forget or err on dating of the Ketoris. The Beis Yosef holds that this does not apply to speach. Sefardim pasken like the Beis Yosef.
Ayn Kelokeinu was added to make of for lost brochas on Shabboz. We are required according to many opinions to recite 100 each day. Bdieved, the praises of Ein Kelokeinu count towards the brachos. There is also a reason to say it according to Kaballah. Sefardim are makpid for this.
When the Ashkenazim came to Eretz Yisroel, they adopted many customs of the Sefardim. Some examples: Lighting the Chanukah Candles earlier than they did in Europe. Although the Yerushalmi Kehillos have proofs that they dress similar to Chazal (I have heard this b'sheim Rav Moshe Brandadorfer), I understand that it was originally adopted from the Moroccan communities in Jerusalem.
By the way, there is a machlokes between the Beis Yosef and the Panim Meiros over what to do when a community moves to a new place with established minhagim. The Beis Yosef holds that we say Kama Kama batel and they to take on the minhagim of their new makom and the Panim Meiros holds that they may continue with their old minhagim.