I'm not convinced. Even if Ami is not ready to ally with the Goketsu right now, or likes to mess with little Hazou, or whatever else that would be a reason for Velorien to interpret our plan as not continuing to the Keiko part as is, she could still be willing to answer us regarding Keiko. Who knows, maybe what she did to her sister didn't have the intended results. Jōnin are not mind readers.
At the same time, maybe she did what she did to Keiko for (in her opinion) good reasons and can't/won't be truthful about her motives despite otherwise wanting to ally with us. So she'll just lie.
In fact, the idea that she will stop all lies just because she is hoping for an alliance is pretty far fetched and, to be honest, a bit much to ask at this point.
Honestly, just imagine if we were in Ami's shoes. We had (in our opinion) good reasons to say the exact things we did to Keiko, we (for whatever reason) decided not to go find Keiko and tell her anything assuaging (yet), we tested this Hazou guy because we could, and now he returns and tells us to [insert all requests and demands from Noumero's plan here].
In such a situation, what would be our reaction as Ami?