Powering mixed 5V and 3.3V circuit from AA batteries
The flaw in your design is that the bottom 3 cells will discharge faster than the top cell. As the batteries discharge their voltage drops. An Alkaline cell is considered to be 'flat' at ~1.0V, however this doesn't supply enough voltage run either of your devices. At 1.1V/cell on the lower 3 cells plus ~1.5V on the upper cell the sensor will get less than 4.8V, and the ESP8266 will get less than 3V when transmitting because the regulator drops up to 0.5V at 150mA. 

So run time will be limited by cell voltage rather than capacity, and the upper cell will have much capacity remaining when the lower cells are 'flat' (but in reality only ~2/3rd discharged). The unused capacity in the top cell isn't realized, while the lower 3 cells don't provide enough voltage to get the most out them. Therefore it will probably be better to simply power both regulators from all 4 cells and run the sensor at 3.3V.