What circuit simulators can also simulate ESP8266 and/or ATmega328?
Microcontrollers do not have comprehensive simulation models. You can maaaybe (if you try incredibly hard) get a vendor model for a GPIO block but even that would be an engineer's fantasy come true. Typically, reading the datasheet and doing some characterization on your own is enough to verify the Chip's analog performance. If you're talking about a CPU emulator, that's something else altogether...