I went 0-3 in this challenge, and had many other less than 3 win attempts. I do not remember I have ever done so badly in any challenge before.
I used Lavahound decks, because it is the obvious sensible thing to do when Fisherman pulls every ground unit and mess up ground pushes. But every a couple of matches, there is always a partner who is obsessed with ground units who send Pekka to fight opponents’ Lavahounds and Battle Ram to fight the Fisherman. I have no idea how to work with these ground troops with a Lavahound deck and lose many matches.
In the end, I used a Graveyard deck to complete the challenge (3 accounts, 8-1, 8-0, 8-1, all 1st try with random partner). It is not a better deck than Lavahound, it is just working better with bad partners who has random decks.
This is a big lesson learned. Finding the theoretical correct strategy (use Lavahound) is not important, the strategy has to take into account the practical problems with opponents and partners.