Update – 22.09.18
I finally had the time to "fully" assemble everything. All things work as expected, RTC, EEPROM, LED, temperature sensor.
A few components are extras and do not need to be placed!
I will upload code snippets to test all the components, should anyone want to build that little thingy!
My boards arrived from the US just a few days after I sent the files.
They look fabulous, quality is really good. They're 1.6mm instead of 0.8 as I mentioned in a log before, but that's not a problem at all.
One stupid mistake is that I labeled D5 and D6 as D9 and D10. But other than the wrong silkscreen there's no downside to it...
I soldered just the Atmega and a LED, flashed the chip to use the internal resonator and uploaded the blink sketch which I set to 100ms because I drive the LED directly with no resistor.
Works like a charm, even after reflowing the chip 3 times @230°C because it didn't settle on it's pads correctly.
Can't solder the other stuff yet because I need to solder the TMP112 first and it has not arrived yet.
Stay tuned :)