You don't have the champs for an unkillable team, so you need leech to stay alive. Your suggested teams lacks this crucial debuff. Vogoth is a good choice for now. I would remove UDK from the team. With Toragi and Harima, you allready have options for decrease atk. And not using UDK in CB frees him to get properly geared for arena, with slow speed in Stoneskin.
Brimstone on Ronda is not as good as it used to be after the Brimstone nerf. It needs accuracy to land now, but nothing else on her skill kit does. I'm not sure if it's worth to put, in exchange for damage, accuracy on her gear only to have a chance for Brimstone. For CB, that may be a good decision, but you cripple her for arena. Phantom touch would be a better option on Ronda for arena or other PvE content like Fire Knight.
On the long run, you probably want to replace Ronda with another damage dealer. If you get the Rhazin fusion done, he would fit perfect in the team. He brings decrease def and weaken debuff, and you are lacking both actually.
tl, dr: Duchess, Harima, Ronda, Toragi, Vogoth.