Adam says:
"I understand the basics of lead-lag in a articulated or semi-rigid rotor"
Sorry, no, you don't. Articulated, perhaps, but the teetering head is different, there is no lead-lag. There is a special underslung hinge to compensate for the speed-up effect, so it is minimal. The blades do not move laterally relative to each other - imagine the imbalance when both blades were on the same side of the circle.
"this has to be compensated for mechanically somehow or else the chopper would roll over the minute it went into translational lift. How's this done?"
It's called Flapping to Equality, and it does it all by itself, as the blades are flexible in the flapping axis. Lead-lag stresses are absorbed by the blades, and the hub is amazingly strong. Look at a BK117 hub to confirm.
And please read a book about all this - takes up too much bandwidth to explain it.