A friend had to reflash a monitor (Acer K222HQL) with a corrupted EDID over the HDMI port. I confirmed that it has three input ports (VGA, DVI, and HDMI) each with their own EEPROM chip next to the port (the friend had to lift a pin on the HDMI EEPROM to successfully reflash it; she should've connected it to ground but didn't). I found a manual online (https://global-download.acer.com/GDFiles/Document/User%20Man...) saying that the monitor supports DDC, implying it does do the multi-peripheral I2C trick.

I have another broken monitor's mainboard where the VGA and DVI's EDID pins go through 100 ohm resistors to {unpopulated 8-pin footprints, as well as the main chip}. I think this means the design considered saving EDID on dedicated EEPROM chips, but ended up integrating the data on the display receiver instead.