I2C Level-shifting? 2N7002DW
I post this here not as a real answer to your questions but to point out a big error in the schematic that you showed in your question. This is how the MOSFETs need to be connected properly.



Picture Source

Notice how the body diode cathode in the MOSFETs needs to be oriented toward the higher voltage side of the level translator.

Another point is that a 2N7002 is a less than optimal MOSFET to be used in a level shifter like this. A much better choice is a BSS138 with a lower Vgs range.