Although the troop trees have not yet been designed, I believe that you can factor in the spawns already. Please see the spoilered image for the spawn locations;
The darkened parts are "Hotspots" where I would like lairs to spawn.
The Hotspot in the Mettenheim / Barclay are applies only to Mettenheim.
The Veccavi spawn area is shared with Snake Sect (and does not have a hotspot).
The Noldor spawn area is Looters until one of the quests for Marius is done (TBD).