High Nick,
Yes for some reason I wrote current, apologies... I have so far successfully programmed the Arduino pro mini which reads temperature from the ds18b20 and sends the data through TTL-rs485 module. I was wondering if I could add in the above setup the esp8266 and after proper programming, have it read temperatures from the same ds18b20 sensor. 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?