So far, Ter Mur and Malas seem underinvolved - Ter Mur makes a sort of sense since it was 'discovered' after Ricardo's adventures (even though there must have been connections from there to Blackthorn, Malas, the 'ML' dungeons, and Ilshenar, because of the statue collection in the museum), but I do find it interesting that Ter Mur has long had a link directly to the Abyss, whilst Malas has an area called 'The Abyss' right next to a volcano. Malas does look a like a severely damaged facet, with bits crumbling into the void, which might imply a link to an area 'devastated' by the creation of Trammel. Could be a reason why it's not linked in to the locations connected with the lantern, but for all I can figure out to date, last place could even be in Heartwood....
I've not checked if there is any 'pattern' to the locations so far though, might try that later if I get chance, but I doubt that's likely to indicate anything.