I created a video that shows how to set up the lipsync in Unity. https://www.youtube.com/watch?v=-kvRoc9uPN8 Regarding the lack of lipsync phonemes, you will just have to improvise by using combinations of the provided blendshapes. To open the mouth in addition to the given blendshapes, you can mix and match blendshapes with bone animations, thus, rotating the jaw bone while using the blendshapes to form the mouth position. This is supported in LipSync Pro in Unity. Let me know if you have any questions. Regarding the eyelashes, duplicating the material is a solution, but it kinda offsets the point of using an optimized character in the first place. It seems CC3 characters only work fully when exported normally without using InstaLOD. The remeshing basically puts you in a position where you have no control over hair or eyelash shaders in Unity anymore, because you reduce your model to having 1 material.
I am also having the same issue with the teeth and have gotten an answer. When it comes to the eyelash issue try duplicating the material and rename it "eyelash" and make it transparent. For phonemes, u have to just work with what we get unfortunately.
Also, where are the phoneme mouth shapes required for lip sync? I see all the other blendshapes such as mouth open, smile, etc. but I don't see the blendshapes for the phonemes in that list?