Do we need to make reservations for lunch if we prefer to eat at a non-tapas like restaurant in Seville? Thoughts?
No. There are a lot of restaurants in Sevilla. You'll find a place to eat regardless.
But, I think reservations are a good idea in general. If you want to get a table at a specific restaurant at a specific time when it might be crowded, and they take reservations, it's a good idea.
Don't totally understand "non-tapas like restaurant" term though. A "tapa" is a small plate. Bars in Spain are known for serving tapas, but any restaurant will serve entrees and smaller plates as well. Spain has a range of different types of places that serve food. It's not all bars.
If it´s a restaurant, you will not be served tapas, but normal dishes. Tapas are appetizers had in many parts of Spain before lunch or dinner.