Ok, I managed Castle Multiball again, and tried to pay better attention this time.
-It starts as 4 ball multiball.
-The dragon starts sweeping it's wings.
-Insert light show is white
-There are playfield add-a-balls available, not sure how exactly, but I triggered at least 1.
-The Martell add-a-ball was in effect, so I did get it up to 6 balls.
-There are 2x and 3x inserts on the upper playfield, and both were lit. Not sure how that was triggered.
-It's pandemonium, but with the amount of blinking on the upper playfield, obviously the goal is to send balls up there. Easier said than done when you are flipping for your life trying to keep 6 balls in play.
I could test all this with the glass off but I choose not to. I like to explore a game by playing it on my own.