Razor - correct, the thin section allows higher speeds before reaching Mcrit and the sweep effectively gives a longer chord and forces any mach waves to propagate at 90 degrees to the leading edge.
The kink in the trailing edge of the BERP blade is where the 2 different aerofoil sections meet and ckearly shows the reflex trailing edge of the inboard section.
3D - I don't comprehend the wisdom of returning to a 5 bladed TR either unless they have improved its lifting capability by cambering the aerofoils.