I used Google Translate to figure out the names of these girls (except one that I already was familiar with), so here are the young hopefuls.
#1 - Yumeka, age 10
#2 - Emi, age 7
#3 - Rie, age 10
#4 - Mikuru, age 10
#5 - Nozomi, age 10
#6 - Ichigo, age 8
Ichigo a.k.a. Ichitan is a friend of Onigokko and is in several photos with the group and its members. The photo below was taken on May 25, 2014 with all the members and Ichitan performing together.
I wish all six girls good luck! I can't wait to find out who become a new Onigokko member!