So was Johari mother-raised after one month?
My bad no, Julia had Johari but put her down after 1-2 weeks. Johari was then hand reared and reintroduced to the troop when she was two once they were certain Julia could cope with her. They both had off display access to one another the whole time though and Julia showed interest in Johari then but never when she had Johari by herself.
Bambuti was the only mother raised gorilla. Prior to Bambuti, Betsy had to be 'shown' how to feed Buzandi/Butouri and when she had Bambuti she had seemingly learnt mothering skills.
Yuska handled Yakini and Mzuri the same way; leaving them to the keepers until they were a bit older and not so much dependent on her anymore. Once they were a bit bigger (about 2) she was fine. It's likely she was unsure of the them at such a young age.
Ganyeka on the other hand was rejected by G-Anne from birth. She had nothing to do with him since the start. Ganyeka was reintroduced to the troop once he was much older, around 2 years old, and from then on was primarily raised by all three other adult females (Betsy, Yuska and Julia) and was often seen being piggy backed by all of them. Betsy was quite fond of him and Yakini. Ganyeka also has a lot of allergy/dietary problems, which also required additional care from the keepers. Its quite possible G-Anne instinctively knew this which is why she rejected him.... Ganyeka was the 'golden child' and was clearly favoured by his father, Motaba though!