This looks as though the users don't have access to a field on the custom form for the request they are copying. I would check the permissions on the custom form for any admin-only fields. 

I've never tried it, but you could edit the setting for timeline calculations? It is a system-wide setting, though, and would apply to all of your users.    Timeline Calculations Typical hours per work day: Set the number of hours in a typical workday for the users who will be working on projects. ...

I can't think of any other setting that would impact it beside their access levels and sharing. 

There is a backend setting that you might want to check, where you can set if resourcing should use the project schedule or the user's schedule. You'll want to set it to resource schedule. I can't recall if it's an option on a template vs a full system setting and I can't get into WF at the moment w...

Do they get an error? Or Is the page just blank? Have you checked their Workfront Access Levels to make sure they match?    You might have to open an Adobe support ticket so they can look at your system internally to see what is happening.     

could you share your filter that you are using on your report and maybe an example screenshot of a proofing workflow where the proof should not be on the report but still is?

The one I provided will look at the "parent" folder instead of the subfolder   Documents Section Final Files Folder (<-------this is what it will identify)  Sub Folder Sub Folder Sub Folder    

I would still have the system admin check their actual access levels in Workfront and make sure they have the same access level (not just license).  Access levels are customized versions of Licenses.   I would also double-check check the dashboard is shared with the user to have view access. I'm not...

https://experienceleague.adobe.com/en/docs/workfront/using/administration-and-setup/manage-groups/create-manage-subgroups/manage-subgroups#remove-a-subgroup-from-its-parent-group-and-make-it-a-top-level-group    

Try this instead.   EXISTS:a:$$EXISTSMOD=EXISTS EXISTS:a:$$OBJCODE=DOCFDR EXISTS:a:documents:ID=FIELD:ID EXISTS:a:parent:name=Final Files