Nice! You even added pullups for the address jumpers! I see you are powering the whole thing with the same power as the servos -- I was afraid of noise on that power line, so I tapped the 3.3V pin on the D1 Mini instead. I guess it doesn't matter for I2C, as long as the logic high is compatible for both. I also tried to make the 5V connection a single trace, so that it can be easily cut, and then you can power the servos separately from the D1.

In any case, great job!

Thanks! If you wish I can send you the Eagle files. I think it is possible to power the AVR from 3Volts as well..

If you received this message several times, nevermind, that was my mobile phone phreaking out, lol!!

Thank you. I don't intend to actually use any of those single-sided designs, it was done purely to see if it's possible. I have a two-sided design that I plan to use -- since practically all fabrication services do double-sided boards anyways, and this is too intricate to etch by myself.