And the later SoDak's were over 40000 tons standard, but were made to fit under 35000 tons standard by messing with definitions. Do a similar amount of bending the rules, and SoDak's and Lex's will both fit under 40000 without any issues.
No, they weren’t. And the weight growth happened after the treaties had lapsed.
What you’re suggesting isn’t going to fly.
The SoDak (1918) design was 42,500tons normal, which including 1,600t oil, a ~500t margin and ~400t feedwater. Technically none of those things would be included in 'Standard' Displacement, however a few others would need to be added (such as a proper AA armament). With a bit of ingenuity and less ammunition than usual, it might be possible to wangle one under 40,000t.
However, the way the WNT worked was that existing ships were rated at the 'normal' displacements (which was very slightly unfair to the Americans and very helpful for the British).
I haven't changed that in the story.
The SoDak ('38) design ended up far over 35,000t, but that was after the escalator clause was invoked, by which time it was perfectly legal.
The North Carolinas suffered similar issues due the change in armament, but again it was legal by the time they were built.
Overall, the Americans took the treaty limits just as seriously as the British in that they genuinely tried to obey them. 'Wangling' was in terms of legal interpretation of the treaty, not outright lying.
However, note that even the KGV design never fell below 36,700t (take out pencil ... err make that 35,500t ... and we'll save some weight during construction).
The only battleships compliant with the 35000-ton limit were the Nelsons. After that, everyone was able (by luck or judgment) to take advantage of the escalator.