Aidan Moffat and Bill Wells aren't men to rest upon their laurels.

The duo won this year's inaugural Scottish Album of the Year Award for their sublime collaboration, Everything's Getting Older, but the Falkirk-bred Glasgow-based luminaries have also been honing separate endeavours which will bear intoxicating fruit in the coming weeks. Moffat has resurrected his solo L Pierre guise for a hypnotic long-player, The Island Come True, and Wells has issued a glorious Christmas Album with the National Jazz Trio of Scotland.

As befits two of Scotland's most exceptional artists, neither offering is run-of-the-mill. Wells's NJTOS is not a jazz band, nor a trio, but rather a vintage pop quintet starring members of Francois And The Atlas Mountains and Golden Grrrls; meanwhile, Moffat's L Pierre alter-ego sees the former Arab Strap front-man, and one of our most vital wordsmiths, converse via eerie and exquisite instrumentals.

Does Moffat explore different sentiments in his non-verbal work? "I think it's fundamentally the same sort of artistic expression from my point of view – I know where it comes from and what it means," he says of his aural narratives, constructed from samples and found sounds. "But its function is entirely different. Usually, if I write a song, I'm trying to tell a story and there's a definite goal, but with this record, it's much less clear. It's up to the listener how they use it."

The Island Come True, L Pierre's fourth album, erects the odd shadowy signpost along the way. The album name-references Peter Pan (and, by extension, that book's celebration of the imagination), while its song titles nod to Buddhism, Macbeth and neon-horror The Fog.

Another distinction between L Pierre's instrumentals and Moffat's vocal work is the concept of record as permanent artefact. "When you record a song it's often not the definitive version, because you know it's going to change when you play it live," he explains. "But this L Pierre album is intended to be listened to alone, at home. It's not something that requires an audience – it's supposed to be a solitary, solid thing. There's no room for performance in that."

Yet the record ebbs and flows with sometimes-otherworldly life: crashing waves, a child's laugh, a sense of ancestry in analogue crackle. "There's something intrinsically sad about tape hiss; there's something very beautiful in scratches," says Moffat. "It's not about nostalgia, it's about history. The music sounds like it's had experience, it sounds like it's been passed along, and by the very nature of that, it sounds like it has more emotional depth."

Such notions of time passing resonate with Everything's Getting Older's themes of birth, love and death. Indeed, Wells and Moffat's collaboration is unprecedented in the canon and continues to find new devotees.

"It does seem to makes a big impression on people," Wells nods in modest agreement. The same could be said for the National Jazz Trio of Scotland's Christmas Album which, true to Wells form, is surprising, melancholy and beautiful. "I hope it's uplifting – I do think the whole Christmas thing should have a bit of glitter and tinsel. But once you've got beyond the stage of childhood, it's bound to have a mix of emotions."

The idea for a Yule-pop anthology grew from Bill Wells's Black Christmas, held at Stirling Tolbooth in 2010. It features bittersweet and haunting yet still-familiar takes on Winter Wonderland, Good King Wenceslas and more. Are there particular carols Wells holds dear? "Well, I completely hate Jingle Bells, so that was quite a good point to start off with," he laughs.

The album is exotic and era-hopping, embracing indie, avant-garde, frosted chanson, 1960s pop, even jazz. "Bizarrely enough, there was going to be quite a lot of jazz on the record," Wells remarks. "I actually had to take some jazz out of it."

This deceptive simplicity underscores Wells's charm: he allies subtle, compassionate arrangements with stunning melodic intuition. You can hear it in the quiet humour of The Power (And The Glory) Of Love – a prescient medley Wells and Moffat recorded long before Gabrielle Aplin, via John Lewis, made an inferior version this week's number one. John Lewis may never be undersold, but Wells and Moffat, solo or duo, are never outshone.

The National Jazz Trio of Scotland's Christmas Album is out now on Karaoke Kalk. The Island Come True is released in January on Melodic.