The editions are almost identical. The only differences are that the 'copying of object relational hierarchy' and 'Large Table handling' features exist only in the Professional edition.

Yes. Databases need not be identical in structure to be compared. Comparenicus detects schema differences and reports them. Non-critical differences do not interfere with table comparison and synchronization. Critical differences (such as a table's primary-key) prohibit comparison of the specific table.

Yes. Comparenicus has a command-line interface.

The Workview is designed to be applicable to many DB 'pairs', so you can re-use your definitions. This is very handy, as in many work scenarios there are several DBs with the same schema, but different data.