With this team I mastered the level 190 battle in 1 attempt: Axel / Thea (Mara) / Heidi (Albus) / Nebula (Cain) / Amira (Axel) / Rufus (Oliver) I needed 0 Jungle Justice for the fight.
First attempt all heroes dead within 37 seconds. Second attempt Heidi survived to finish the root and the last golum thing off - took him/her/it about a 80 seconds fighting alone. Seems that a lot of this is just pure luck.
It worked for me on my first try...I thought it wouldn't take that much luck, but I may have been wrong. Can you tell me how many attempts you needed for level 190?