I imagine at this point, they're basically pushing this to next-gen and rebuilding assets to keep up.
This game has been such an odd disaster. On reveal, it genuinely seemed like the trailer could've ended with 'out now'. A multiplayer game that just lifted the AC ship mechanics seems super easy to put together, and I don't think they really NEEDED to do major overhauls on what was already there. But now it's been three years, the project seems further from finished than ever, and even AC has kinda moved away from the boat stuff. No pun intended, but the ship has sailed on this concept.
As for the three unannounced titles for this fiscal - WATCH_DOGS 3 is largely confirmed, the new project from the Mario x Rabbids team should be ready, and I imagine the Avatar game that Massive was working on is the third. (If Avatar 2 was originally scheduled for a late 2020 launch, a game in Spring 2020 doesn't seem impossible. And a major game release could help reintroduce the brand ahead of the next movie.)
Edit - Splinter Cell also seems totally doable. Maybe that instead of Avatar.