Yeah, you already have a lot of the necessary cards upgraded, so I'm going with Icy on this one. Ray of Light/fractal/hope is a very potent FG grinder without many upgrades (I personally play it with 17 upped cards, but you only need 8-9 for the shards and rays of light), and it gets the highest win rate of any deck I've fought FGs with. Of course, the sweetest part is being able to beat all the gods that rainbow fails against with relative ease (seism, dark matter, divine glory, etc. I got 5 consecutive gods that I almost always lose against with rainbow and won them all with elemental mastery, lol)
I don't know how well shrieker rush does against FGs. The win rate will probably jump 10%-20% if you add 6 shards of gratitude, lol, since it will pwn any god without a whole lot of creature control, and it gets damage out really fast. I'd guess a win rate of around 25%, but what mileage are you getting with it?