They were heros, but not because of their lying. They were heros in spite of it! It is entirely possible to accomplish their same goal without lying.
I'm a martial arts instructor and theoretician. I teach misdirecrtion. For example, if a man holds a gun on me, I can say, "Please, I hate it when someone puts a gun to my head." If then he, out of spite, holds the gun up to my head, I know several ways to take it away from him withhout any danger of being shot.
This is what God did at the 2nd Battle of Ai: misdirection. It is moral and right, unlike lying, which the Bible clearly teaches that God hates. Please, if you're going to deal with this issue, deal with the passage in Prov. I quoted. How do you interpret it if you believe lying is okay in some circumstances. (Which, by the way is situation ethics, and opens the way to a wide range of "justifiable" sin.) Shall we do evil that good may come?