On the Commanders' signing DT D.J. Davidson, a source indicates the team is planning on running some defensive sets with three bigs, so adding more depth in that area was a big reason for the signing. Davidson has nose/DT flex, and imagining him playing alongside Tim Settle is attractive.
The expansion draft will have two rounds, with 12 total picks per round alternating between the Fire and Tempo, and will follow a snake format, meaning that after choosing 12th, the draft will 'snake' back around and the Tempo will also select 13th.