Of course you can. Just remember that, while she still treats Jerba harshly, she never goes as far as Zira did (i.e., hitting him and leaving a scar and so on).
Ok, I went ahead and took the role of Kas'im. That means that just the roles of Jerba, Nala and Sheba are left. If anyone decides to take Jerba or Sheba, their profiles are in my first post.
Jerba is an Outlander lion with Zira-like fur color and, as an adult, a brown mane. As for personality, he's a bit like Kovu. However, in this respect, you can vary his personality as much as you feel you need to and in any way you want so that he doesn't become a complete Kovu clone.