Arduino sketch for Proportional valve

The project consists of writing an Arduino sketch for a low-pressure air proportional valve. I would like PID control of the valve. The valve will be controlled by a NEMA 17 stepper motor. The stepper motor will be controlled by a A8825 motor controller mounted on a breakout board that I have specs on. I want to use an Arduino Nano to control the A8825 controller. If you recommend another embedded platform, please explain why. The stepper will only be rotating 50 steps (25% of a revolution or 90°) The scope of the sketch consists of writing a PID control of the motor based on a 0-5v pressure transducer input or a locally set setpoint by an operator (more below). A 2x16 led display will report the current setpoint. The system will have Wi-Fi capability and should be able to communicate and receive remote setpoints though the Wi-Fi connection (ESP8266 ESP-01 Serial Wi-Fi Wireless Transceiver Wireless Module Development Board LWIP AP+ST). Normal operating conditions would allow the network to set the setpoint, however, a local operator would be to override network setpoint locally via a two-button switch (up and down) circuit. The setpoint therefore, will have two methods of being set, 1 remote and 1 local. The local setpoint takes precedents. I am considering adding the P, I, and the D values as local push buttons (up & down) also, so that the operator can control the response of the valve locally without the need to reprogram. (we can discuss after the award of the project) There is not a time limit on this project. I am open to recommendations, although I am extremely pressed for space, so SIZE MATTERS, when making recommendations.