Donni Yes, by using tags and permissions. Your admin/mod, when they reply, would need to add a certain tag to the original post. In the backend in the permissions settings you could set up permissions for that tag.
In short, you would set your permissions up so that by default, only admins and/or mods can reply to posts. But, then you would set up a tag based permission which would say, if this tag is included, anyone can reply.
So that only admins and/or mods can use said tag, you would use the start discussions / start discussions without approval permissions with that tag. Therefore, if someone tried to start a discussion with this special unlocking tag, and they weren't the admin or mod, they wouldn't be able to.
So, if set up correctly, anyone could start a new topic. But, no regular members could reply. Then an admin/mod comes along, edits the original post and adds the special "unlocking" tag (named whatever you want). And, they reply. Now anyone else can reply.
I'm saying this from memory and have not tested this exact scenario, but, I have set up fairly complex permissions and set up a kind of faux wiki. I set it up so that if someone adds a tag called "wiki," anyone can edit that post. That worked great - and so I think the above will work as well.
Flarum's permissions settings and tag based permissions settings are really nice.
