Hey @Zenb!
Selfishly, I suspect that because dbt Cloud’s scheduler is pretty simple to set up, there’s not a lot of demand for lots of people building explainers on how to use it 
We should do a better job of making that information available though - what were you you searching online that brought up mostly Airflow?
A lot of companies do use Airflow alongside dbt Cloud, but unless you have other tools in your data transformation process (e.g. an ML process that you need to trigger in a different system after a dbt run completes) it’s definitely not mandatory and you’ll be well served by using dbt Cloud’s built in scheduler to avoid the extra complexity.
To answer your questions:
Short answer: yes! Long answer: probably, unless you have a particularly complex setup as described above.
I don’t normally use BQ myself so I’m not 100% sure, but it’s supported in dbt Core so I don’t see why not!