Not much to report today - no progress on the hot ATmega here's what I tried:

1. Removed Y1 the 16MHz crystal with the incorrect footprint
   
   1. No change to power consumption
2. Tied RESETn low
   
   1. No change in power consumption
3. Power via VBAT in case TPS6305x isn't good with backfeeding
   
   1. Reduced power consumption to 100mA - but output of buck-boost was only approximately 1V - current limiting was in effect

So...I figure I have two choices for where to go from here:

Option 1: I remove the ATmega from this board, which has the rest of the components populated allowing me to verify their operation (buck-boost, battery charger, maybe even the RTC, display, ADC if I wire up an external controller).

Option 2: I have the three OSH Park fab'd boards, stencils, and Digi-Key parts. I can try to assemble a minimal set of components to test the ATmega pinout and connections in the absence of other components.

Perhaps a two-prong attack is best...