Questions about Security and Sensitive Information in DUST Workspace

Hello, I've questions regarding sensitive information and security in DUST I would like to know :

If Dust Team (developers or other team member) have access to the content of shared files in the workspace ?
Is it necessary to have Entreprise plan or the Pro plan is enough regarding maximum security (Entreprise Grade security) ?
Is there best practice guidelines/practices regarding sensitive documentation to manage Dust Workspace ?
Where are the data stored when an agent has retrieved data from file? Same question for the log ?

Thank you