Based on the analysis (https://docs.google.com/document/d/1BaaykHtpstttWJx_-4DQNwkVkLsit_jpUpqOIl1X4bk/edit) the plan is to

• limited use case for the start: single existing Linux (Fedora Linux?) installation
• dual-booting with Windows as next step

That means the UI can be simple

• offer the option in this limited case (no further questions UI intraction needed)
• offer possibility (checkbox near the radio option?) to unlock encrypted partitions
  • this will be probably required to be safe - have enough information about existing systems