At this point it seems pretty obvious to me that Lockhart is a 1080p console for their Xcloud data centers, but they might be struggling to find a good PR strategy for a consumer version of Lockhart ("Next-gen with 4TF??"), that's probably why we haven't heard any concrete statements.
Makes just too much sense imo. Xcloud is focused on 1080p streaming, using Xbox One S consoles. And it seems they think people who want to experience 4K will rather buy a real console:
Also, power consumption is a big thing for data centers. Just look at this article comparing Xbox One S and X:
www.anandtech.com
Xbox One S: 107W under load
Xbon One X: 172W under load
That's a lot, and if Lockhart has a similar advantage vs Anaconda, maybe even more, because it was built up from the ground for that purpose, this is going to be huge. Putting Anaconda in their data centers when Xcloud is limited to / or mostly used for 1080p, would be a gigantic waste, especially at the scale they are considering.