I was thinking I would have individual sketches programmed on each MCU that control their own leds, but the programs would all be initiated at the same time and so that's the only necessary control signal.
I know there are PC based programs and DMX etc but I'm trying to do this with low cost and I thought with neopixel/FastLed strip programming experience I could do a good job with an Arduino based system. BTW I have found 5m WS2812B strips (5V, waterproof, 1.25" spacing) for $16 via ebay.
It looks like there are several mesh libraries and these sound promising: ESP8266WiFiMesh, painlessMesh, APC220 wireless mesh. I think I really want to stick to WIFI because OTA. Maybe use a 433 separate module to do broadcast commands and WIFI for updating?
The diy xmas light page looks good an I'm searching for others as well. Thanks.