Social media only will not be accepted as a genuine attempt to find NZers to do the job. The job will have to be advertised on a far-reaching recruitment platform; Seek, Indeed, TradeMe jobs etc.
The job title is not the same as your current job title, if your employer is named on your ESV, you will have to apply for a new work visa as you can only vary your employer, not employer and job title.
"If you have an Essential Skills Work Visa, and your job is not on a skill shortage list, you can only apply to change your employer.
You need to apply for a new work visa to:
change job
location, or
to change employment to a lower skill-band."
https://www.immigration.govt.nz/new-...ng-a-work-visa