The first CD of this set was originally released in 2004, followed by the second CD in 2011. I don't know the history but I suspect that the first CD was intended to be a one-off. The presence of three actual Moody Blues and two ex-Moody Blues members on the second CD suggests that they were impressed by the original album and may have encouraged the sequel. I can certainly understand how and why they were impressed.
The Moody Blues didn't have a huge number of hit singles, and their biggest UK hit (Go now) came very early in their career and didn't make any impact in America. I am therefore not surprised that it isn't featured here. More surprising is the omission of both Question and Isn't life strange, which were top 30 hits in America and bigger than that in the UK. Perhaps they weren't suitable for adaptation to bluegrass, but it doesn't really matter what the reason is. The songs chosen all clearly work well in a bluegrass style.
The credits on this combined release are mostly limited to who sings on what tracks; the musicians are not credited on individual tracks and I get the impression that some are not mentioned at all. So I don't know which tracks Ray Thomas and Mike Pinder played on (except that their tracks are on the second CD), but the other three each sing lead on one track - Justin Hayward (It's cold outside of your heart), John Lodge (Send me no wine) and Graeme Edge (Higher and higher), If any of them contribute instrumentals, the credits don't say.
Nights in white satin, being the outstanding song, is inevitably one of the highlights. It is one of five tracks on which John Cowan sings lead vocals; he is clearly a fine singer who I need to investigate further.
I've not come across Jan Harvey before, but she does well on It's up to you and Say it with love. Her daughter Emma was only 8 when she recorded Voices in the sky, but given the quality of the other tracks, you can be sure that track would have been omitted if it wasn't up to standard. I's a quite remarkable performance for a child of that age. Vince Gill (I know you're out there) and Ricky Skaggs (You and me) each sing lead vocal on one track.
I am familiar with some of these songs, particularly via the compilation The Singles+, which I own. I'll confess that I don't play it as often as it deserves and this very differently styled collection will inspire me to play the original Moody Blues more often.
I could continue enthusing about this collection for a while yet, but the seemingly unlikely combination of Moody Blues songs and bluegrass stylings clearly works for me.