I wonder how much of the recording is natural. I'm not surprised by the
"frog" sound, since it sounds much like a wood wind.
The panning seems to be natural, but the tail of the reverb sometimes
sounds artificial. Some pipes could be natural, but they do sound also
much like a DX7 glasses voice.
Résumé:
Let's assume the recording is completely natural, then at least the
microphone positions are unnatural.
Extrem panning and long reverb tail by providing a that transparent
sound?
IMO the final reverb tail sounds suspect. Even if everything should be
natural, I suspect that there's no position in the "room" were you could
experience this sound, this most likely requires dedicated microphone
positions.