Hi,
I've been doing tableau dashboards for last 4 years everyday and almost perfect to handle any situation in Tableau and getting data from different data sources.
I've worked on google analytics before and i am sure i can do part-3 and set-up the dashboard for you.
As you said, your data is pretty much consistent, you've already done the main part. I've taken data from RSS feeds, xml files, excel, SQL and many more and cleaned for dashboards in alteryx, knime and SSRS.
I can do part-3 and give you your dashboard.
This might be my first freelancer project, but i am 10 years exp professional in BI, Reporting and data handling.
Thanks,
Amit