In my opinion, option 1 is the best because data consumers in Vietnam would love to have an unifying relation for their own local maps (instead of mucking it out on their local maps, which is both time-comsuming and very complex). I'm all for making other relations for other countries disputing in the area as well. Also, as far as I know vietnam generally claims all of the spratly and paracel islands, and the vietnamese government has not made any specific claims regarding to what islands specifically do we want to claim (also see https://vi.wikipedia.org/wiki/Louisa_(r%E1%BA%A1n_san_h%C3%B4), vietnam also dispute the louisa reef).