Can I send a suppression list to Facebook and Adwords in my journey? Every use case I've seen so far is about sending an ad on Facebook, but is it possible to create a Facebook custom audience from journey builder to then populate a suppression list in my display buys?
Short Answer: No.
To do this, you would have to download the audience and exclude them directly for the 3rd party provider.
This is a example of how this would work with Facebook.