Given that your hypothetical operator is moving from single pilot ops to multi crew ops, there would be no reason for your equally hypothetical Company director to lay off his current pilots, as the numbers to fill seats doubles.
In such a scenario, the learning curve would be way too steep for pilots to transition to the left seat immediately, and it is unlikely that any insurer or regulator would permit it.
At the very least, a program would need to be developed (the current buzzword is “pathway”) that would probably have the company’s existing pilots in the first officer seat for at least a year and 500 hours to learn something of CRM, support pilot duties etc. While their local knowledge in remote area operations would be of some value to the new hires tasked with training them, single pilot “bush” operations do not necessarily develop the complex decision making skills needed to operate a complex aircraft in a complex environment while keeping operations legal and safe. Resilience, yes, sound decisions not guaranteed.
Suitably experienced new hires would be unlikely to take kindly to being regarded as less senior to their trainees, and that concept in itself throws up human factors questions.
If the aim was to have the new hires eventually train themselves out of a job, they would need to be employed on a fixed term contract. Your hypothesis needs to also consider the industrial implications of any such arrangement.