Adding RAID to an existent installation

I have TW installed on SSD with an encrypted Btrfs partition. Now I’m looking how to add and an encrypted soft RAID 1 as an additional data storage.

  • Is it ok to go with Btrfs for RAID or it would be better to use XFS or even ext4?
  • Projected partitioning is displayed on the screenshot below. Is there anything I have to or should change?
  • Would the system still boot up in case I disconnect drives RAID would be located on?

Thanks in advance!

Proposed partitioning