Dracon, Splinter Cannon
2 Trueborn, Splinter Cannon - 61
The Dracon can't take a Splinter Cannon, only the Trueborn can. They have the same BS, but it cuts out the possibility of precision shot shenanigans.
I would stick with the vehicles version - Warriors and Wyches on foot don't last long, although perhaps the two large packs of beasts hurtling towards the enemy will draw fire away from them. Apart from that, I've never used beasts, and I don't really play tournaments, so I've not really got much guidance for your list.