You would need to create a "user" in your system that has that email as their login ID.

You aren't able to brand the email from address but you could add your company logo to them to make them more familiar for users.   It's in the account settings for proof.   YOURCOMPANY.my.workfront.com/proof/account/settings

Could you accomplish this with a calculated field using the same data holding projects? You could do some if statements for it to auto-populate based on previous selected data?

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