So we currently have 6 chars and 4 slots claimed, with 3 girls and 3 boys as accepted chars, 1 girl and 2 boys and 1 of either gender as claimed slots.
That would mean we'll have 4 girls, 5 boys and one of either gender, adding up to a total of 10 characters if the claimed slots are filled. Then the number of open slots is either 3 girls and 3 boys or 4 girls and 2 boys depending on the gender of the last claimed slot.
We'll then either need to have 6 more people create chars, the rest of us who have already created 1 character create a second character and 1 person creates a new char or anything between the two extremes.