Interesting...while Mi's resolution at 100% is subpar, it does have over twice the pixels, and excluding the DoF issue(one should assess resolution on in-focus subjects, or better, at/near infinity), and probable close focus performance degradation, I'd say it has respectable total resolution, surpassing the Mate and the Pixel(Pixel 4 experiences a degradation in this respect so it's hard to say about Pixel 3). This is especially evident in the sample with the building, using browser magnification to bring the magnification of the competitors up to the Mi's level, where the Mi is evidently superior, except in certain bushes with very thin branches where it failed to resolve much. Regarding the optics, this Mi unit has a midframe dip on the right 1/5 of the frame while the bottom right corner is clear again, contrasting with the Mate unit which has a worse left 1/3 of the frame overall. All within normal variation should also be expected in units that reach the hands of consumers.
The lake scene seemed to have all the units focusing on the foreground reed, therefore less useful in assessing resolution, but the Mi has a clear win in that one regardless.
The Mate's AI is still probably better left off, the green and red are utterly eye-searing on my wide gamut display, though from experience it could look more balanced on a regular sRGB IPS like my tablet's.
Are you sure all the samples labeled 3x are the same magnification? They certainly don't look that way with the Mate's notably narrower FoV, in fact assuming the Mate 3x is real 3x(also, correction here that it doesn't have native 5x, it swapped the periscope back for a conventional 3x), the others may very well be 2x.
Night is largely as observed before, except with the added comparison with the Mi, auto on the Mate is strong but night mode is much weaker and often not worth the tradeoff, though Pixel 4's night performance seems weaker than what I've seen before.