sorry for the late response. I've been quite busy lately and have not been answering to questions in the forum.
You're right, the microcontroller on all ESP32 boards are identical, so selecting the Nano32 board should work. I should probably add a bunch of boards to the PlatformIO build system, but it takes time which I don't have atm.
Pumbaa and other MicroPython frameworks are quite different. They are all based on the MicroPython interpreter, but the hardware drivers modules and classes are quite different. Pumbaa's drivers maps one-to-one with Simba's drivers, while the default MicroPython drivers has another interface, often unique per board. I think MicroPython are trying to unify the drivres (machine module) to make scripts portable over a range of boards, but I don't know the progress.
Pumbaa will never be obsolete, it's just an alternative to standard MicroPython.