If I had to guess, I think Ella would've made it even harder for the MC. Knowing what we know currently, Lvl 4 Ella could've easily handled the situation but that's not in character for her to help the MC with his "training". She loves to sit on the sidelines and "cheer" for him. Also, we know Xanthe and Nico were watching so Ella's role wouldn't have been too out in open.
At most, I think she would've gave us more advice while also telling Klaus "anonymously" about our plans. Whenever Ella sets up a stage for the MC, she intentionally makes it harder for him. Look at the Jake fight. She tried to handicap the MC as much as possible(minus telling Jake all of the MC's powers), regardless of if his friends would be caught in the crossfire or not. She likes to secretly pull the strings on these events, so I have no doubt it would've turned into a bigger clusterfuck if she was brought in.