Can you post the generated link.xml file? Maybe there's an error in the xml.
Also check for a duplicate link.xml in the project. Maybe Unity is using the wrong file...
Are there errors in xcode when you run on iOS?
@Budde88 - I followed it exactly as well. It generated the link.xml just fine and it works on Unity. However, it doesn't work on iOS for some reason.
@Alex Chouls - There is no duplication and the only xcode errors are the same Semantic issues it had before I switched from Mono 2x to IL2CPP. Here is the link.xml:
<linker>
<assembly fullname="UnityEngine">
<type fullname="UnityEngine.SpriteRenderer" preserve="all" />
<type fullname="UnityEngine.BoxCollider2D" preserve="all" />
<type fullname="UnityEngine.Camera" preserve="all" />
<type fullname="UnityEngine.GameObject" preserve="all" />
<type fullname="UnityEngine.Canvas" preserve="all" />
</assembly>
<assembly fullname="UnityEngine.UI">
<type fullname="UnityEngine.UI.Image" preserve="all" />
<type fullname="UnityEngine.UI.Button" preserve="all" />
<type fullname="UnityEngine.UI.Text" preserve="all" />
</assembly>
</linker>