That was the one that crossed my mind too. Seems like a good fit. They could do worse that have a Legends based Suicide Squad. It might tie in better to the Darkseid thing they were going for in the Justice League. From memory, the squad would have been:-
Deadshot, Boomerang, Blockbuster, Flagg, Bronze Tiger and Enchantress. Chronos and Vertigo were also in there for later squad use IIRC. The Joker was captured in Legends too, and this could easily be replaced by Harley. A Nightshade could get them in an out, or have Enchantress do that and keep Katana.