It moves! Not pretty yet, but it's alive and I'm controlling all 6 PWM channels with blind output sine waves, and no feedback. 

In the video, the top board has the ATmega328PB and the FETs. Since I designed it to drive motors outside of the business card body itself through the three pins in the upper right, I'm using those to drive another business card that only has the motor windings in it. I started out assembling a few different boards with different components so I could isolate and test the sub-systems. Time to put it all together!

Plot of my blind sine waves:

When the sine wave is positive, I modulate the upper FET of the 1/2 bridge for a given phase. When the sine wave is negative, I modulate the lower FET of the 1/2 bridge for a given phase. Certainly not optimized, if it wasn't obvious in the video, but very inspiring progress to me.

I may not be using the best PWM channels on the 328PB. The frequencies don't match, and SimpleFOC docs suggest using different pairings. Coils are getting pretty warm quickly. Only using 500Hz and 1KHz at the moment. 

But it moves!!!!

Here is a "good sine..."

That is the voltage measured between Phase A and B showing how the sine profile mixed with back EMF and the other phase. Certainly more work to be done!