Those rumours contradict. 4 TF for Lockhart, 1440p60, >10 TF for Anaconda, 2160p. Performance delta is way more than the resolution delta, meaning devs would have to cut back on Lockhart visuals, meaning the frame targets aren't any sort of targets at all. Plus a slow CPU on Lockhart could mean different game experiences.
The only dual combo is the idea that ignores the 4 TF and 10 TF numbers and has Lockhart as a binned Anaconda.
Developers will simply treat Lockhart as the redheaded stepchild (i.e., the same way they do with XB1 original) and concentrate more resources on the premium systems visuals & performance profiles.