Just guessing here, but I do not see a quest::spawn() where you can set the NPC attribs like the #spawn2 command in-game. It's likely you'd have to use the existing Pet data to spawn a helper around the players level? That could result in a large script, but I think you can test the player $level or something and spawn the pet that is closest.
Or, re-write one of the quest::spawn commands to accept level, stats, size attribs.
Let me know when you have that done. ~snicker~ j/k - I'll take a look, too, soon as this project @ work is done kicking my ass.