“will utterly burn up.” The Hebrew is more literally “burn up” meaning eradicate (cp. 1 Kings 14:10).
“those coming after you.” The Hebrew is literally, “burn up after you,” but the rest of the verse and the context indicates that those coming after are descendants and those who would have been part of the dynasty of Ahab. They were all killed.
“who pisses against a wall.” A crass idiom and cultural way of referring to the men.
“slave or free in Israel.” The meaning of this phrase is uncertain, and there are at least six different possibilities that have been postulated by scholars. The same phrase is used in 1 Kings 14:10 (see commentary on 1 Kings 14:10).