I've only heard Nightingale, the rest isn't fully recorded yet. So I can't possibly speak for the album, other than I've been told it should apparently be quite varied/diverse. So I'm not drawing any conclusions/assumptions from the sound of Nightingale.
For Nightingale itself, not sure there's a huge amount I can say but to respond to your specific question, it's not a super synth heavy track or anything, but there's plenty of keys all over it.