Mister,
The Eastern Code, CCEO, c. 811.1 states, “From baptism there arises a spiritual relationship between a sponsor and the baptized person and the parents of the same that invalidates marriage.”
So while the relationship according to the Eastern Code is an impediment to marriage, there is, as you note, no such impediment in the Latin Code. Canon 1 of the CCEO is quite clear that “the canons of this Code concern all and only the Eastern Catholic Churches, unless, with regard to relations with the Latin Church, it is expressly established otherwise.” As Latin Catholics, you are subject only to the norms of the Latin Code.
In the Pio-Benedictine Code of 1917, which was abrogated with the promulgation of the Johanno-Pauline Code of 1983, this relationship was an impediment to marriage, but it could be dispensed by the local ordinary. The CCEO also allows this impediment to be dispensed since it is ecclesiastical (man-made) law (CCEO, cc. 795 and 1536).