Whether hiring a freelancer, contractor console game developer or a boutique development agency, you need to know exactly what specialists you need and check their competencies accordingly. To build a console game from scratch you will need a team of video game developers, QA specialists, UI and UX testers at least.
Portfolio. List through the showcases an applicant can be proud of, evaluate the quality of the games, their marketing success, etc. Ask a developer about their work during a project: what challenges they have to face, what their role was and what the game story was all about.
Soft skills. Communication with a team will define the success of the game. Talk to your applicant and see whether you are both on the same page. Also, check whether your future hire is passionate about the gaming world and holds a hand on the pulse.