Assuming you made a second profile for the google things, and opened a new Google account without any personal data, and have no email, contacts and calendar in that profile, what data should they get?
As long as you keep things strictly separated and don't have personal data in the google profile, they only get that someone is using an app.
Graphene does no magic, it makes it harder for google to get data and offers phone usage without google services. But when you use Google, you use it and they will collect.
The moment you have contacts in that profile, Google will know who you are simply from looking at the people in your contact list-someone of these will have you in their contacts, and if there are a bunch of people knowing you under the Name XYZ, than it's pretty sure you are this guy.
And from that point you could use stock Google, makes no difference.