Seraphim,
Obviously, a Catholic would not believe in the thing about being in the "land of the living". In fact, I translated that a bit inaccurately. Before the body is buried, it is still referred to as a living person, but not after the burial. Whether or not this is a pagan belief, or just a custom that evolved from the intense grief that children feel at their parent's passing and a manifestation of an element of denial, I do not know.
I also don't think that bowing, even if it is complete prostration, constitutes idolatry, like offering incense to an idol does. In the Old Testament there are many examples of prostrating to humans and to angels.
Undoubtedly, if the family in question were traditional Catholic, there would be rosaries and the De Profundis, etc as well. I recently posted a prayer in Classical Chinese that Catholic subsituted for the part of the funeral ceremony in which an eulogy praising the deceased was proscribed by tradition.
I suppose then, there would also be no scandal in wearing traditional funeral garments? I'm not sure if they are Buddhist in origin or not. They consist of a white headband and a white hooded robe, etc.
Essentially, what I am asking is that how far can a faithful Catholic go in trying to be faithful to his culture and the Church at the same time. Obviously, parts of the funeral rites that Alexandre de Rhodes described as superstitious and contrary to the faith would have to be abandoned, by I'm just wondering if the external obsequies can still be performed.