About the larger main hinges, the small holes and the orientation of the upper leg hinge can be seen in this video at 1:04:
However, that shows only the direction of the upper leg hinge. But I suppose that the lower leg hinge should have the three holes at the same side as the upper leg hinge.
And about the M3 30mm bolts and the small 3D printed hoop holders:
I initially had the same conclusion as you that they bottom out on the thread in the standoff, and that they should be 25mm bolts in order to fit.
But once I tightened the whole arm end (with all the three 3D printed parts), it became nice and tight.
I am not sure what happened there
Maybe it only felt like bottoming out as screw tightens pretty tight to the small 3D printed loop holder hole too, and because the standoff turns around easily inside the big 3D printed part.
Although, I think I even tried assembling only the small hoop holder through carbon plate to the standoff to see if it was bottoming out. But maybe I remember wrong.
Or maybe I just used (the) force in the end to make them tight. Well, I don’t know but they are good now.