Currently, Fivetran only lets us provide a "prefix" that will be used as part of the destination schema - the rest is inherited by the source schema name.  So for example, for a MSSQL connector, I might chose my destination prefix to be "myPrefix", but the destination schema name turns out to be "myPrefix_dbo" where "dbo" was the schema name from my source.  I appreciate that Fivetran may do this to help avoid duplication and collisions; however, I can manage that responsibility on my own.  I have several use cases where I need much tighter control of what the actual, exact, full schema name will be in the destination.