Is Expanded DDL supported for objects whose underlying objects may be in replication?
If the parameter SP_OCT_REPLICATE_ALL_DDL is set to 1, then the Expanded DDL support is enabled. The Expanded DDL support exists for objects which are not in replication. Such objects include tables and sequences and also a wide range of other objects like procedures, functions, users, views, etc. which do not form part of replication.
For objects such as stored procedures, functions, views where the underlying objects MAY BE in replication, the expanded DDL replication will still occur. For objects such as users, there is no ambiguity as there are no underlying objects here. The parameter is meant for tables and sequences not in replication and is also meant for other objects which cannot be a part of replication, regardless of underlying objects of such objects like stored procedures, functions, etc., being in replication.
In nutshell, the fact that the procedures, functions, etc, have their underlying objects in replication will not prevent DDL replication on these (if SP_OCT_REPLICATE_ALL_DDL is set to 1) just because their underlying objects are in replication. The Expanded DDL will work regardless of the underlying objects in replication. For tables and sequences it will only work if they are not in replication.