Senior interview questions test whether you can keep a system correct when its data, timing or ownership changes. A fast query can still duplicate an order. A low model error can depend on unavailable future information. A scheduled report can run successfully while reading an incomplete source partition. Describe how you would detect these failures, not just which service you would choose.
The executable tasks use explicit dates and tie rules so their outputs are reviewable. The design questions include constraints that rule out a superficially plausible answer. Treat them as a short design review: identify the required grain, the available evidence and what the proposal cannot guarantee. The scenarios stay within BigQuery's role in a wider data system. They don't claim that SQL alone configures orchestration, access or a production model monitor.