Here are the Mechathun decks I used for Lazul and Rafaam, in my recent ASM marathon run.
For Rafaam, I'm using Dorian combo since it's safer than Thaurissan + Enchanter, you don't need to spend a turn to setup the combo. Late game could be dangerous in this fight, and having to spend 9-mana on a turn to setup the combo can kill you.
I put more cheap spells than before to have more chance in having a cheap spell for the Kaelthas trigger.
For Lazul, I'm still using the Thaurissan+Enchanter combo since the fight's easy, and doing the 9-mana setup is rarely dangerous.