Subversion carries the risk of weakening the Realm and causing a civil war, and while I don't mind that too much, it's still a bit early for that. Buying time for us to implement either Empire or Metropolis would give us a far stronger position for the civil war. It would also cost us the use of our prophet when it could be put to better use helping Luseng.
If we delay them long enough to implement our plans, then we won't really need to care a lot for the dictates of the Deliberative. With Empire, we would have done far worse, while with Metropolis, we would have spent months "following" their orders, and would have gotten Nellens to support us, giving us sufficient influence.
As for how we can creatively interpret their orders, we were always intending to gain back Luseng's strategic resources so we can use that to count as striking against the Realm's enemies. For the 10% tax increase, we could interpret it as a 10% increase in tribute, linking it to the one about increase Luseng economy. The Immaculate Order could be blamed on the Shikari dying, preventing us from having any monks to spread the faith.
In addition, the ship must be carrying a lot of obols, thus making it a very attractive target for all the pirates that are in the area. While we haven't contacted them yet, we could do so and point them in the way of the ship. If it sinks, it would take time before they realize what happens, and would mean that they would not be able to confirm how exactly were their orders relayed to us. Furthermore, the loss of the ship gives Sao an excuse to carry out naval operations, which can further buy us more time.