Matt Fraction and Ben Templesmith continue the story of “Juarez, or Lex Nova and the Case of the 400 Dead Mexican Girls,”—by turns hilarious and horrifying—in the second issue of IDW’s ongoing exploration of the rich fictional universe Steve Niles has created. Niles, teamed with Kody Chamberlin, weighs in with more explosive vampire action of his own in part 2 of “Dead Billy Dead.”