https://hackaday.io/project/6456-esp8266-din-8-channel-wifi-relay-controller

and it really got me focused on using an ESP8266 as the brains of the operation. The touch screen module I want to use can communicate via SPI and I'm sure I can find a temperature / humidity sensor that can output SPI. That would significantly decrease the I/O pin count I would need especially if for the downstairs unit, I could use an SPI GPIO expander to drive the relays.