You guys are over-thinking the Generations breakdown too much. The breakdown is pretty simple. There is no need to separate Series 1 into FoC vs non-FoC. Everything that has been released under Series 1 is Fall of Cybertron. The easiest solution is just to call the sub-cat Series 1: Fall of Cybertron. Just as Series 2 packaging will all have the Thrilling 30 printed all over the box/card. The full breakdown for the Generations cat could be as simple as:
Generations
> Generations (2010)
> Series 1: Fall of Cybertron
> Series 2: Thrilling 30
The only break in the sub-categories comes from the original run of the Generations figs which we have come to call as Generations (2010).
Too late for me to think, elaborate on my post further. I may add to this in the morning.
-- SoS