The mission is difficult and very prone to RNG. I don't think the specific deck you make matters that much, since you gain random cards throughout the mission... but it does have some influence. I tried the mission again today after reading this post and I was fortunate enough to win on the first attempt.
Here's the deck I used (yes, I paid for Leprechaun Imps, but I was extremely lucky to get 3 warlords from packs (I crafted the 4th copy). I only played one Warlord during the mission though.
Here's what the board looked like on the final turn:
My advice - don't play anything in lane 2 on the first turn, since it will be prone to splash damage from Lightning Reeds in the water lane. On the following turns, play as many minions as you can, except if you have weed spray... in that case, save 3 brains to take out annoying admiral navy beans, sting beans etc.
I actually got the Octo Zombie from the Transformation Station and it was bounced back to my hand... I played it in the water on the last turn and just filled every other lane. The buffs are from the one Warlord which I played on an earlier turn.
The AI loves to play Doom Shroom and Jumping Bean... almost every time I play this mission, I see them both played. Keep that in mind as you play the mission and as you build your deck.
