Mhmm. I know what you mean about getting used to their voice in order to understand what they're saying. Sometimes, I have the same problem but the subtitles help a lot with that. They've been getting more clearer as the new updates come out which is always nice addition. You're correct about Luka; she is a special vocaloid that was released with a bilingual voice-bank.
Anyhow, I'm glad you liked them. Yes! I'm quite a fan of Japanese music in general (diverse genres as well).
I haven't heard about WORLD ORDER before this but I have to say that their song was rather catchy. The PV also had me laughing quite a bit which was a pretty fun experience. Thank you for sharing it and Happy Birthday!