Selina and Pi are definitely male. Rosie looks female, but it just might be she hasn't yet developed the male characteristics. I'm thinkin' you have three males there.
I'm happy to see these photos, sorta bring a bit more light into the day.
I notice from the recent photos, where they are in a tub, that the left most one also has much less flaring on the rear marginals. And Rosy is the largest, so I'm inclined to say that one is female, the others are showing male characteristics.