… I’m honestly not sure of what you’re saying here. The most efficient what in a best practices context, for one thing? 
How dated is Blender v2.66a for your purposes? It’s not the most recent release, admittedly (I believe that the most recent release version is v2.71), but do the more recent versions have features, changes or fixes that you intend to use for your game, and that 2.66a lacks?
Out of curiosity, given your focus on tools, what prompted you to choose Panda over Unity? I would have thought that the tool-chain would be one area in which Unity had the advantage over Panda.
I gather that ninth decided to not work on YABEE while anti-Russian sentiment was high; I don’t know whether that has changed. Of course, deathless could always have a shot at updating YABEE, but I don’t know how complicated that might be, as I don’t know how much Blender has changed its API between versions (which I seem to recall ninth mentioning as one of the reasons that YABEE breaks between Blender versions).