A godzilla list, especially a choir godzilla list relies on shooting (with a heavy dose of counter-charge ability) to destroy the enemy. You've missed two important items in maximizing the ability of such an army:
1) Your flying Tyrant should be configured with two Twin-Linked Devourers. A CC Flying Tyrant doesn't fit into a choir army as you want to shoot units and force them to fall back. A CC Tyrant will block your army's LOS and if the psychic screams work their magic your Tyrant will be left sitting in the open to be shot by the entire enemy army.
2) Not taking a thrid Dakkafex is a huge problem. You need the maximum amount of shooting in a choir army and the Dakkfexes are your bread and butter. You need 3.
Some other issues with your list:
3) Your list comes to 1,502 points by my reckoning. You need to eliminate 2 poitns.
4) The Implant Attack on your walking Tyrant is a gigantic waste of points, as are the lash whips on your Tyrant Guard. That unit will not likely see combat in the game and if it does it should be as a counter charge with Genestealers, Raveners and Carnifexes. In short, you don't need Implant attack. Lash Whips can be useful, but again with the amount of counter-charge your army packs I think the extra 2 Attacks are more useful than the potential to deny extra attacks (an ability which is often of little to no use at all).
5) In a 1,500 point army, 16 Genestealers is waaaay too much. You will be absolutely fine with two units of 12 or even one unit of 8. I prefer smaller units as they are more easily hidden behind the Carnifexes. I normally recommend extended carapace on all your stealers, but in this army configuration if you take small enough units you can often keep them from taking any enemy shooting before they charge into combat.
6) Consider taking a unit of cheap Spinegaunts to tie up charging enemy units, capture a table quarter or tie up an enemy shooting unit in some cases. They are cheap and useful.
7) You have listed your Zoanthropes as having "Scream" and "Psychic Scream". I assume you mean "Warp Blast" and "Psychic Scream"? If so, I'd recommend taking one of the three with Synapse instead of Warp Blast to give you some Synapse in Escalaltion games where both your Tyrants start off the board.
8) You should really take the +1 Wound on your Heavy Carnifexes. It is relatively cheap and it adds even more T6 3+ save wounds to the army, something that makes it even harder for your enemy to overcome your list.
