There are at least three different ways to replace the controller in this keyboard.
The stapelberg directory contains the docs and configuration for using Teensy based controller created by Michael Stapelberg.
The alvicstep directory contains docs and configuration for directly wiring a Teensy2++ to the existing controller board. This follows the pinouts described in https://github.com/alvicstep/tmk_keyboard, which is where the name comes from.
The kintwin directory contains the docs and configuration for using BlackPill based controller.
All three hardware solutions should work with the same keymaps
In addition to the drop-in replacements of the stock controller above, the directory "keyboards\kin80" contains the files to support 80 switch modification of the keyboard, compared to original 86 switches. Kin80 keymaps are not compatible with keymaps that are located inside of kinesis directory.