I understand what you are saying but wouldn't it create unnecessary delays when editing or updating the threads? And many people would probably PM that account instead of this.
You can mention in the thread to contact official person for any related queries or send PM only to you in case of project related information
Yes but there will still be people who contact the OP. Also, we will have to contact the OP every time we need to update the thread. More than anything it will be an inconvenience to the person helping us and we would never want that

What you think about a self moderated thread and changing it later as per your needs?
Self moderated thread are not received well by the community and we don't mind critics so the plan is to keep it open.
What could work though is that I create the thread, then someone like you posts the announcement as a reply and when this account becomes a Jr. Member, I edit the OP to make it the announcement and you remove your post.
But since that would take a month I guess its better to just buy an account for a few dollars.