So the Primalist Hunter Archetype gains an evolution pool that he can grant evolution's to his animal companion with.
I war reading up on it and I noticed that it got a little bit wonky when you combine it with an animal companion.
1: An animal companion does not "technically" have a base form, so I guess that your animal companion cannot take any evolution that requires a certain base form. (this gets weird when you use something such as an Eagle)
2: Then there are certain evolution's that require a previous evolution that grant a limb like the sting evolution that requires you to have the tail evolution to select it. I guess by RAW, you have to still select the evolution that grants the limb before you can gain the upgrade such as sting even though the animal companion already has such a limb.
This could probably be put into the rules forum but, I have no idea how to properly address the issues with this archetype.
I'm hoping we can get some constructive imput on how to handle this archetype.
The Primal Companion Hunter is banned in PFS, so you're only going to be using it in home games, which means you can work with your GM to figure out how restrictions like that work.
My suggestion is that you look base shape and evolution pre-requisites more as 'things your creature must have', not specifically as evolutions.
For instance, an evolution requiring a quadruped base shape could be applied to a wolf or horse animal companion.
Similarly, if it has a tail, you should be able to take the Sting evolution. Applying common sense is important, too. A horse has a tail, but it is made of hair. It shouldn't be able to take Sting.