Some tables for T268572: Convert SecurePoll to AbstractSchema can be migrated to AbstractSchema without additional work. To my knowledge, they are:
- securepoll_entity
- securepoll_properties
- securepoll_questions
- securepoll_options
- securepoll_lists
The tables.json from https://gerrit.wikimedia.org/r/c/mediawiki/extensions/SecurePoll/+/657196 has the expected schema for these tables. These can be migrated first. The others require schema changes.