Very nice and complete presentation of your project! 
Since I’m a self proclaimed DS18B20 wrangler 
I have some input that might speed things up, even if not necessary 
// The number of bits of temperature resolution
// 9 = 0.5, 10 = 0.25, 11 = 0.125, 12 = 0.0625 degrees Celsius
#define TEMPERATURE_RES_BITS 10
// Temperature conversion wait time, in milliseconds
#define READ_CONV_WAIT 800
// We'll do the "wait for conversion" ourselves using a timer,
// to avoid the call to delay() that the library would use
sensors.setWaitForConversion(false);
The conversation time with 10 bit resolution is only 187.5 ms, so no need to wait for 800 ms. You don’t even have to wait for the 187.5 ms if you don’t want to. You could execute other code and come back after ~200 ms and just read the result of the conversation, which only takes about 30 ms.
I’m using two timers in my project to do this “hit-n-run” on the sensors
@Mauricio_Lima There is examples of how to use multiple sensors hidden somewhere in the forum. I can’t remember where so you have to search for your self