ruckus doesn't have a shield in front of him that protects from stuns, so use your reload to deal with him. just avoid his high burst damage before you stun him, after that he has to spin his weapon for a second to get it back again.
If you have Chain Reaction legendary, place some Sticky Bombs around Evie in Ice Block and time your detonation right, so you can punish her for staying in it for too long.
When fighting against her, the "Deep Roots" legendary is mandatory. She will reduce your healing anyway, and by rooting her you can render mobility potential unusable for a few seconds