Regarding power consumption statistics of different raspberries, I made some tests over the last few weeks to get to know what is the exact runtime of a RaspberryPI board on a battery.

For each test, I fully charged the battery and then let a board run as long as it shut down due to empty battery. On each board I had a cron script logging uptime every 5 minutes so I got to know the exact time it remained alive.
Each board had only base OS load running, no intensive tasks. The OS was on default settings and I applied no power-conserving tweaks for any of the boards.
I repeated the test 3 times for each board, and the results for each board dffered less than 30 minutes for each run. The presented results under are the average for each board.

Unfortunately I have no PI Zero, so could only do the tests on models 1, 2 and 3.

Based on the results it seems that RaspberryPI model 3 easily outperforms both models 1 and 3.
However, I suspect that having a different OS and kernel versions on different boards leads to some variance, so maybe I should also run the test using identical OS/kernel.