It depends on how the customers are stored (users, custom post type etc..) and as well as how the information about their status (free, paying) is stored as well.
If for example the customers are post types and the customer status is stored in a custom field, then this might be easily solvable by changing the ordering based on the custom field.
To add additional data to the results, a custom code will be needed for sure, especially in case of complex things as star ratings. I'm not sure if that is actually possible. Here is a knowledge base about result templating which allows making direct changes to the result layout files. A custom filter code might also work.Best,
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