Can you get all of Google Pixel features on Graphene OS and if not what features will not be there?
Graphene OS features
Most features that use google services will not be available without installing an optional google services package
Most features that google advertises (from my own personal experience) can be obtained just by downloading the specific corresponding google app associated with it. For example, all the fancy photo editing tricks and things that they show off can be obtained just by downloading the google photos app.
Two noticeable features that don't currently work on GrapheneOS are Android Auto and NFC payments with Google Pay. Note, however that optional Android Auto support is coming soon.