The problem is that once you get to the limbs their orientations are all over the place (which is good) but the gravity setting no longer works right.
You could select all the endpoints of the instances and send them up on the z axis after realizing them, like this:
or down:
I moved the resample after the realise instance node and I set the resolution of the original quadratic bezier to 1 to deal with only 4 points per instance.
It still only effects the “tip” point of the limb with the compare node set to; integer not equal.
If you change that compare node to; float, greater than, you can move more than one point, at 0 it will effect all 3 points (1,2,3 NOT 0) this does not look to good. At 0.5 the last 2 points (2,3 NOT 0 or 1)