That's up to them. Probably, the freeholders would try to meet in the evenings to accommodate working people. There is no exemption for freeholder meetings in the Open Meetings Act. Freeholders are not a layer of bureaucracy. Then the board of freeholders is dissolved, regardless of what the voters do with the freeholders' proposal.
Initiative is a petition calling for a new law or a change in an existing law.
If approved by the voters, the change takes place. If that's the only change you want to consider making, it would be easier just to do it under present township form of government. However, it would be cheaper only if commission salaries were reduced accordingly. The best way to get a sensible charter is to elect sensible people as freeholders. There is no need for a cumbersome charter.