React is simple.

First I'd start with creating the database in Postgres. Create tables to hold data and any views needed to represent joined tables for convenience. Once that's settled, the express server comes next to create a CRUD API to work with the data and handle user authentication and authorization. This is dead simple and once it works there's little you need to touch. The database handles any data dependent business logic.

By this point you can make API calls and use the application through any REST client.

So now I just need to create a React client to consume the API and give a great user experience. Don't need Redux. Grab React-Router and a couple packages for UI components and you'll be up and running with the MVP in no time. Checkmate.