OK, we really need to hear from the surprisingly-not-dead Nanook now.
Meanwhile, though: Natlaw was a watcher, not a full investigator. I consider it unlikely that the Scum would have had both a watcher and a normal investigator, and yet he knew (as confirmed by Astral) what Astral was. This implies that Astral is Scum.
Vote Astral
Also note that Astral recommended yesterDay that Nanook investigate him: This is certainly consistent with the assumption that Natlaw’s claim was an attempt to save a valuable Scum, since Godfathers benefit greatly from being investigated.