I love the idea of a Thieves' Guild that ties together the Rogues. (I recently acquired Cormin!) A couple of thoughts:
Melaine: Maybe it's just me, but I can't read this name without thinking it's "Melanie". I like both Concealment and Stab in the Back for her.
Kelasho: It should be "Thieves Guild" (you've switched your i and e there). And my suggested wording for Brutal Strike is:
When Kelasho the Brutal attacks an adjacent figure, he may attack that same figure 2 additional times.
With 4 attack, that's pretty Brutal!
I really like the theme of the Thieves Guild power -- Kashlo as the boss can send his Rogues out in pairs, and they're making silent signals to each other across the crowd, etc. The figure doesn't scream "Rogue" to me but as a Brutal boss-type it works OK. I'm guessing that armor is why he's stayed alive to rise to the top of the guild...
BTW I have done cards for both these figures (not my unit designs), so it would be pretty easy to make cards for
Melanie Melaine and Kalsho. Let me know.