Custom Fields - Join and Unjoin Issues

We are using Wrike in our PMO for tracking all of our projects. For reporting purposes, we have created Custom Fields (CF) that we apply at the highest folder or project level of each project.
The problem is that there are several other fields in various projects with the same field name as the CFs that we created. Therefore, Wrike tends to Join those fields when we look at the projects in Table view.
We have a few questions about this:

• If I unjoin a field for my view (table view) does it unjoin the field for all users or just for my view? 
• Does my unjoin 'stick'? - Currently it seems that if I (or any user) UNJOIN the fields that are auto-joined by Wrike that this does not hold - Wrike auto-joins the fields again at some point (overnight?). 
• For CFs that we intend to use for the whole team, if we change the field name now will that cascade to all projects where that field was previously added?
• If we can/do change the field names will this stop the Wrike auto-join?
• Can any user change these team CF names? Or should it be the original creator of that CF?
• Do the CF names need to be changed in a certain place or at a certain level within our structure? (e.g., at the highest parent folder/project level?)

Thank you all in advance for any help with this. I have read very many posts and tutorials on CFs and did not find these answers. If the questions have been answered elsewhere, I apologize for asking them again and will appreciate being directed to the answer.