You can order by any column that you wish.
In SQL Server the syntax of ORDER BY is like this.
ORDER BY Col1 ASC, Col3 DESC
All data types use the same syntax.
I assume that the ORDER BY would look something like this.
ORDER BY isdate(Obsolete) DESC, isdate(not_relevant) DESC, isdate(assessed), isdate(published), isdate(implemented), locally_adapted DESC, guidanceType DESC, nice_ref DESC