If you want the right candidate for the job, you only need 6 things:
1. A proper position description which sets out the requirements of the job
2. A person specification setting out what the successful candidate needs to perform the job
3. A rigorous selection process based on the PD and PS, to choose the top 4 candidates to interview
4. A targeted interview questionaire based on the PD and PS, to ensure the candidates can do the job and integrate into the company
5. Well trained interviewer/s
6. A rigorous reference checking process
That's all there is to it. No need to complicate the process. Remember the KISS principle.