The HW apps are relatively simple; however, they use them as a springboard to ask bigger, more complex questions in their follow up. Basically, "if this HW app was 1000 times bigger, how would you handle X."
For the React HW, they asked how I'd do global state management, caching strategies for maximizing efficiency, and how I'd further build out my tests. On the Rails side, we discussed testing and managing long queues with service workers.
The in-person interviews were definitely the hardest part.