Exporting from Oracle enterprise edition to standard edition reaches schemas limit
Apparently a full=y is allowed.
Converting An Enterprise Edition Database To Standard Edition (Doc ID 139642.1)

The only way to properly convert from an Enterprise Edition back to a
Standard Edition is through an Export/Import operation. This way you will
get rid of all Enterprise Edition specific Data Dictionary objects, as the
SYS schema objects are not exported. The Standard Edition EXP utility is
preferred to be used to export the data.


So apparently all the EE DD objects are not transfered. 
Followed by dropping or excluding while exporting the EE schemas.