Cleon
Legend
Feats seem right.
Concentration, Craft (mapmaking), Decipher Script, Forgery, Hide, Knowledge (the planes), Move Silently, Sleight of Hand might be good for the first 8. Knowledge (geography) would be thematic, but I don't know if it makes sense since they're extraplanar.
Well while it seems plausible that they'd know a lot about terrain from gathering all these maps, the description does say the maps they make are often inaccurate or totally false, so they may not know any geography at all!
Overall, I think I'd give them Spot instead.
I think I like often evil a little better than usually, but I can go either way.
I agree, they seem to lean toward Neutral so Often Evil should be enough.