I believe there was another introduction shortly before Tundu's death, so I don't believe there are any suspected pregnancies. Intros tend to just last a few days to my knowledge. I'm not sure if Kibibi has been introduced to one male or both, as she remains with her mother, Uhura, through intros.
Generally, the two adult females and their immature offspring live together, and one or both of them may be with one of the two males for short periods. The set up of the exhibit allows for easy movement of rhinos between different areas. There are two 'main' yards, and a series of smaller ones. This accommodates three to four groups/individuals as needed.
How many calves have the two adult females had each since arriving at Monarto? I believe one is from South Africa and the other from Singapore Zoo.