superJj:
Indeed you are correct in saying that the mini is redundant but I am experimenting on whether such a connection would be physically ok.P.S. What if I power ds18b20 with 3.3v (which works on esp8266) run between Vcc and Data the 4.7k resistor and then send that data line to pin2 on esp8266 and pin 2 on the mini?
If you really want to do this just as a pointless intellectual exercise, OK, but don't show it to your mother. DS18B20 can run on 3.0v and I believe it uses the same pullup 4.7k. As I said, it makes more sense to have one device read the sensor and distribute the data.