I believe Lovecraftian cats can leap to the moon in groups, so yes, cats can ride ghosts and vice versa.
Cats can do anything. Just ask them.
I wonder if the Iram Solis will amplify a cigarette lighter to the point where it's dangerous. I also wonder how the real dragon will react to being hit with flame.
Plus "Whoo" may be Hector about to change sides, and Brother Marcus is about to play his card.
EDIT:
It occurs to me that the lovingly Spark-crafted gun would make a fine club. It's large, sturdy, and Vipsania could easily smash Hautwyrm over the head with it.