The little blurb above the liner notes says the special ost was handled by the commenters (Tsuchiya and Koduka), so I guess both arranged (they don't really say what they did).
reincarnation uses live organ performed by
Tomoyuki Asakawa.
prelude II is (evidently) SMT2 title and hallucination II Chaos (from 2 I think)
They said a soundtrack will be coming, yay.