I believe that white is associated with death, so avoid that. But colors are generally good. (My grandmother grew up in China, so going off things she said, which makes it all about 90 years old).
Personally, I would not try to do an asian theme of fabrics -- just make a very American quilt. They will understand that this is a traditional American artform made as a special honor to welcome a baby.
I recently made a baby quilt for a couple from India -- they obviously appreciated it, even though it's not part of their tradition, nor is it particularly practical in India (though they are currently in the Pacific NW with their baby, so can use it here.)
RST