[@Komager]
For most characters, they have been enlisted either three days prior, or on the very day they move to the castle. The opening IC post will have these characters cross the bridge and enter their new base of operations; and given some time before their first meeting for any interactions. 
Some characters at my specifications will already be at the castle that will help organize the newcomers. Lancelot will not be present, but the keep's 'manager' will be present and give a speech on Lancelot's behalf.