Per TEIIDDES-1794 there are more areas Designer needs to add support for temporary tables:

... the full array of temp table stuff we currently support is:

• Teiid global temporary table (a virtual entry - which from an engine perspective can be on any model type)
• Teiid temporary table (not a schema entry in the design time metadata, scoped to a session/block)
• Teiid temporary table backed by a physical table (not a schema entry in the design time metadata, scoped to a session/block - the physical table could be a temporary one)

Eventually we would also like to have an ease of use path to simply create a teiid temporary table and have the backing table created on a source automatically - similar to the data shipment join temporary table creation.