1. Can we run "Migration wizard" for each case type seperately?Yes, when you go & update Application rule by selecting only the case types which you will be needing.
3. Will migrated attachments get deleted from attachment table after migration? The record will still be present in Data-WorkAttach-File with few meta data. AttachStream property will be removed as part of migration.
8. Attachment Wizard can only move Data-WorkAttach-File? not all Link-Attachment instances? It moves only the File streams. Both Data-WorkAttach-File & Link-Attachment tables will still have the entries.
Please let me know if someone knows answer for remaining queries.