Wanwan has a YouTube, Bandcamp, Soundcloud and NicoNico. But for now, contacting him via Bandcamp would be the best choice, but so far if I want to get the most efficient communication with him, I have to use a translator to translate my speech to Japanese (as well as his speech (if it is in Japanese) to English). That's tedious job for me, as evident when I uses translators to translate my fanmade's Seihou game's text. I have to input the EN text in, and then switch to JP mode, making any fixes to the JP mode so that it suits the context rather than input the raw, uninteresting Google Translated text into my game.
The reason I crave for MIDI versions of Wanwan's Kaisendou music is that in his works there are 3 (or 4 if I count Michel's theme) tracks that I really likes and want to make a cover of, which are: Mankind's Salvation Plan (Iesua's theme), Angelic Night (Saraka's theme, contains bits of Sariel's theme), Absolute Lily (Tamako's theme), to which the final one is the most pleasing to hear because of the shamisen and the church organ playing in unison in that track, which is something rare for "ecclesiastical" music in both real life and video games. And if Wanwan releases MIDI versions of Kaisendou tracks, then it would attract more fans to the Kaisendou games, who will then make cover versions of these tracks, as long as they don't rip instrumentations from the actual tracks for their covers.
Hope all of you understand this.