I must say I hadn't considered Davram Bashere as a potential Darkfriend, merely as a man who tests those he is in alliance with to their limits. He always seems to want to find out how far Rand can go, how strong he is. Tenobia, however, I think could very well have given herself to the Shadow. It is inconceivable that any Borderland ruler would leave a stretch of the Blight undefended just because she is impatient and impulsive.

I think you are right about both Davram and Tenobia dying in the final book and your theories on Perrin and the Broken Crown make perfect sense.