You area otherwise that we aren't talking about Halo in the SW universe or SW in the Halo universe. Both universes are bound by what they have in their own universes. Which, of course, means that nobody in the Halo universe starts out connected to the force. If it did, the entire idea of the Gravemind consuming the ability to use the force is null, because he would already have the capacity. So choose one. Either he can gain the ability or he starts with it. Although your choice doesn't actually matter.