Thanks for everyone's helps!
We made it back to the states with all of our animals with no problems. We ended up just boiling them all out as best as possible, and putting them in checked baggage. Before we left we ended up sending money to the New Zealand DOC and all our information except for the quantity of each species. Then just before the end of the trip I was able to text my wife who then emailed them the quantities. They then mailed the exporting documents to us. When we came into the USA we told them that we had hunting trophies and they quickly x rayed them and then looked at one of the heads to see if it was dry. They really had no interest in the documents, but I am still glade we had them. I learned a ton from this trip, most of all is that TSA and Custom officers have no idea what is going on.
I highly recommend just putting the heads in your checked baggage, as it cost very little for extra bags. Also I left some hides at a taxidermist in New Zealand and it has been 9 weeks with out hearing anything from him. Not to mention the cost in shipping.
I will do a write up on our trip in another section when I get time. Very enriching, difficult, and successful trip