1. Develop a Transformer script that is applied to the documents being migrated. It is beyond the scope of Support Services but is open for you.
2. Try the following scenario:
- copy just the document library to target without content
- check that the target document library has the two CT of questions
- copy content only of source library with the following Configuration
-> Apply filter on Items to include just .msg
Apply content type mapping as applicable
-> Apply filter on Items to include just .doc
Apply content type mapping as applicable