Build the best midi/standard guitar I can with what I got.
What I got is an old Fender Stratocaster from Korea in bits, in a bag, some previous great looking effort towards this, and lots of suitable microcontrollers.

The frets will be read for capsense and connectivity. The strings will be electrically isolated from the body to serve as the return path and allow the strings and frets to then act as a matrix keyboard.

Individual strings will also be directly read with a custom pickup and fed into an ADC.
Zero crossing can be used to detect frequency, harmonics and bends, and the raw amplitude can be read to determine portamento on the corresponding midi note.

The custom pickup is made from opened audio isolation transformers, magnets, and a binder clip. Each core also has a second winding for an additional analog audio signal.

Add a couple knobs, an IMU, and some other capsense pads connected into the midi stream.
Perhaps a display on the top edge of the body.