Editors on both sides of the Atlantic and their respective powers that be (upstairs, the suits, the bean-counters) have agreed, so Oath of Fealty is now the official (until something breaks) title.
The comment from someone upstairs at Del Rey (“upstairs” is a hierachal terms, in this instance, not architectural) was that this title would work if we weren’t trying to go outside the core audience. Which I’m not, though the Paks books have pulled in some very interesting readers.