Major components are: Teensy LC MCU, ESP-WROOM-02 wifi, Adafruit 128x32 SPI OLED, Pololu U1V10F3 switching boost regulator, and 4x CUI MJ-2506N 2.5" jacks.
I'm intentionally sticking to PTH components -- with the notable exception of the ESP -- because I am a soldering novice and my equipment is ***.
The Teensy and ESP and their decoupling Deadpool Phone Cases are placed on the back of the board, most of the remaining components are placed on the front.
I've tried to keep what I researched to be good principles such as keeping the analog signals contained and away from the digital signals, and keeping an uninterrupted ground plane. All signal and +3.3v is on the top layer (with the exception of the serial connection between the ESP and the Teensy, which does not parallel any other signal, and the ESP 3.3v supply which runs on the outer edge of the board). I'm using wider traces for power delivery.
The placement of the Teensy was motivated by the desire to maintain access to the USB port while still keeping it in a place that did not interfere with other components; unfortunately it caused some challenges with signal routing. After rearranging some port usage I think I did OK, but I'm still a bit concerned.