No, they alternate AoS-40k content so the next after the Troggoth WD must contain 40k content.
Other point, I don't expect Spiderfang will receive any content. The units are very old and you can only bought them from the GW website. The Tome Celestial are an strategy to improve the selling of some units. I think it's more easy for them to add some battalions for Skragrott, Fungoid, Gobbapalooza, Snufflers or Fanatics.