1.) Yes they are! Individually, the Lekgolo aren't very intelligent, but when they link up into colonies, they gain increased brain mass. Despite a colony being made up of numerous Lekgolo, the colony itself is a single entity with one consciousness. Currently, we've only encountered three colony formations in the story. The Mgalekgolo (the bonded pairs we fight against in the games), the Sbaolekgolo (the colonies that operate Scarabs and Harvesters), and the Thanolekgolo (a swarm of Lekgolo capable of mimicking other living creatures). 2.) Rtas 'Vadum is still alive, and still the Shipmaster of the Shadow of Intent. There's a book coming out in December that covers his endeavors after Halo 3. Some of which include military operations with UNSC forces, and an attack on Sanghelios by Jul 'Mdama.