I will presume your PH will drop the trophies off at the taxidermist over there for mounting or dip and pack, correct? If you have the mounting done there you will be able to have the "finished" trophies sent directly to your house, with the help of an "import agent" who can also arrange truck shipping from the port of entry to your house. If you dip and pack your horn and hides will be processed by drying hides, cleaning skulls and horns and packaged for shipping to you taxidermist. You "might" save 15% over all by doing your mounting there. Pros and cons of doing mounting over there, you can read all about it here on this forum. If you hunted South Africa I can highly recommend Bullseye Taxidermy there. They did 4 mounts for me and I am very pleased with their work.
If you want to have your own taxidermist do it here you will still need an import agent here to receive your dip and pack animals, clear them with a couple of agencies here and then ship them to an "approved" taxidermist first for retreating if your taxi is not "approved" to receive them. Your taxi will then mount and ship to your home or you pick up.
Basically your billing will be:
taxidermist over there to mount or dip and pack
shipping from there to a port of entry here in the USA
import agent here
fees to US Customs, etc.
shipping to an approved taxidermist and then your own and then mounting.
You'll find many import agents by digging on this website and I'm sure others will chime in.
Make sure you get quotes for everything before you agree and keep good contact with the taxidermist there and here and the import agent. They all have to coordinate but a good import agent will do all that for you. They will also make sure all the paperwork is correct before it gets shipped here to avoid losing your trophies to fish and wildlife for improper documentation.
Welcome to the forum!