Right at the end of the Foundations course, I started working on the views for my first project (while taking the following courses in parallel especially for Firebase)
Ended up scratching that project but learnt a TON from it. You can read about it here
Totally agree with your determination to focus on the “Launch your first app” journey and not get lost in other tutorials, I think this is the way 
you can always expand later but you really need to build a strong foundation first and this is something the CWC courses provide
Good luck!