Two stakeholders, one yes

One person closes. The other leaves notes the closer must consider. If they refuse to pick a closer, the post stays in draft until they do. You cannot invent authority.

Write the closer on page one of the kickoff. Revisit it when someone new joins their side.

Product checks claims first. Marketing checks voice second. Or the reverse, if that matches the risk. Parallel reviews produce contradictory notes on the same afternoon.

Give each a due time inside the overall deadline so the second person is not handed the file at the last hour.

When notes clash, do not average the design. Ask the closer which note wins. Record the choice. The person who "lost" can see that it was a decision, not a slight from your team.

Your team should not pick a side in their politics. Facilitate the choice.

Two stakeholders should add a known number of days, and that number belongs in the schedule. If the reality is twice as long, show them the dates. Often they will simplify once they see the cost.

Until they simplify, reduce how many posts need both of them.