Good answers, thank you very much. In regards to 3:
I'm running https://www.okystar.com/product-item/hc-sr04-ultrasonic-sensor-module-hc-sr04-distance-measuring-transducer-oky3216-1/, taking a reading every 3 minutes.
I can't find the power consumption for the 3,3V option that I have, but for example let's assume (from this Turn power on and off to ultrasonic sensor (HC-SR04) - #18 by Sakibjoy123) that "My HC-SR04 has a peak of 15 mA as it turns on, and then it consumes 6 mA" so the draw would be:
15mA + 6mA ~ 21mA per each run
so 20 times per hour
that means 20 x 21mA = 420mA per hour
so 10A per day
Adding the Firebeetle (FireBeetle_ESP32_IOT_Microcontroller(V3.0)__Supports_Wi-Fi_&_Bluetooth__SKU__DFR0478-DFRobot):
- Operating current: 80mA in average x 20 (hour) x 24 (day) = 38,4A per day
Altogether roughly 50A per day. If you're getting 60% capacity from the 13400mAh in 35 days, then my math is wrong somewhere, right 
?