Hello! I'm the author of this project. The website contains a full step by step tutorial https://awot.net/en/guide/tutorial.html for deploying a standalone react app on ESP32.
Depends on the content and the amount of clients a mcu could handle at a time. For and arduino using a simple http server (no https) I think you can have up to 5 active connections before it crashes.
Any that implements the Client interface. It is not limited to WiFi modules but for example also works with Teensy and the Ethernet shield. I use it with ESP32 and ESP8266 most of the time.
This kind of projects would have made my life much, much easier.
I would have loved to see a "setup" guide in your getting started page.