Personally I would leave all the new kits at home and have gargoyles and fexes instead. I like the idea of six fexes charging up the field.
I disagree with much of this. The Exocrine and Hive Crone are actually good and useful. The Former is practically mandatory if you ever come up against Grey Knights (a Dreadknight will easily wipe an entire Carnifex brood on his own before they ever get to strike). Gargoyles are pretty horrid in general though I can see the use for them as a screen for
MCs. They took a rather bizarre nerf in this book.
However Carnifex spam is undeniably the strength of the book (Heavy Support in general is very strong). So I'm on board with the overall idea suggested in the comment.
As for the list:
Flyrants are solid, if you can find points for toxin it is a great investment.
Tervigons are poor now. Loads of points for not a lot of benefit. You could get 4 Zoanthropes for those points get more psychic powers and more synapse and more threat.
Hive Crone is good Harpy is horrid drop both of them. The Crone provides Haywire and a S8 vector strike the Harpy provides almost nothing of value. The
HVC is still a poor weapon compared to the Devourer.
Exocrine is good but not sure he fits with the
FMC spam you've got. There really is no reason not to take 3 Heavy Support in any Nid list.