Espressif has moved the SDK to GitHub. At this point, It is version 2.1. I have no indication that they have done anything with the ADC Feature I requested. I have not updated to this newest SDK yet. I will do that before I spend any time working on firmware.
New component costing:
The 74LVC2T45 level shifter chips are US $0.32 each in low quantities. The PCA9306 I2C level shifter are about US $0.60 each in low quantities. This results in the costs of the level shift components arount $1.50. The original single part costs around US $1.25 each in low quantities. This is not a big difference in cost but it does affect board space.