OK, guys, I just did about four hours of A/B on the full RP2 with O2 pads vs. LCD-2 (v1, not v2).
Conclusion? The LCD-2 are definitely bested. I think they actually have a bit of veiling in the mids, and the RP2 did a clearer rendition of voice, guitar, piano and string, with a faster attack and more presence in the upper mids/lower highs. I never would have described the mids of the LCD2 as veiled, but I felt it today. Mind you, this is not night and day, and someone could prefer the LCD-2 and not be blamed.
At the top end, I think the RP2 does a better job on cymbals, and massed strings have more rosin-sound to them, and more bite. The bass is really, really close between the two.
Comfort: LCD-2 wins. I have to try the LFF headband mod, too much pressure on a tiny spot on my head.
I can't wait for someone else to do the complete RP2 mod and give feedback. I'm pretty proud of these, so who knows, maybe I'm just kidding myself. I ran some sweep tones today and found no particular hotspots/dropouts, which is comforting after doing all this by ear. Hennyo, hope you get some FatMat soon since you also have the LCD-2.
Note I updated photos in the OP.