Well, since it seems that nobody ever dealt with a setup like this before, I gave it a (somewhat random) shot, connected yellow & red to red (L1), and blue & black to black (L2), stood back with a fire-extinguisher on the ready, and flipped the switch.
And... everything worked just fine.
Top and bottom oven heat up, lights work, controls light up, and no smoke anywhere (all hooked up to one 40amp breaker).
Perhaps someone else, who might come across a similar weird monster (and this thread) will be able to save themselves some head-scratching...
