I'm not posting a schematic, I'd rather spend that time doing more research instead of drawing a picture. This is such a basic setup, you do not need a picture. It's just a Mega board with a ESP-01S connected.
I already stated that all 4 pieces of hardware are running the blink sketch. What code are you asking for?
The distance is about 50 feet max, open air between them, which seems irrelevant.
I just need guidance on the proper library for what I'm trying to do with the hardware that I have, and help flashing the ESP modules if needed. Maybe just using ESP boards without the Megas would be better, but I need about 20 pins for either input or output.
Thanks