We have an audit happening across our content. Is there a way to set up an account in SharePoint on-premises (2013 & 2010) and SharePoint Online that we could give the Auditors access to everything but in read-only?
It's impossible to give the auditors access to everything but in read-only permission.
In SharePoint on-premise,only site-collection owners can run audit log reports.
In SharePoint online,you need to be a member of the default Site Collections Administrators group or a farm administrator to run Audit Log Reports.