Edit: As of Oct. 28th, the youngest victim whos name was released is 10 months old Mila Cohen who was murdered in her home.
At this time, not all the bodies have been identified, and of those that were not all names were released to the public. Of those whose names were released the youngest are Omer kedem siman tov, aged 4, who was massacred with his entire family. And Yazan Zakaria Abu Jama, an Arab Bedouin boy aged 5, who was killed when a Hamas missile hit near his home.
Beside these we have photographic evidence of Babies bodies from the attacks released by the IsraelPM twitter (X) account. Warning, graphic images
And finally we have first hand accounts of Zaka volunteers who collected and treated the bodies and remains of the murdered. Just one example from an interview with a Zaka volunteer depicting what he personally witnessed in Be'eri:
We found families that were simply shot to death. Some of them burned to death after they murdered them. We had to care for bodies of children and babies. They didn't distinguish between anyone they just went around and killed anybody they saw in front of them. We saw children, we saw small bags with babies inside.
As time will pass, more bodies will be identified and their names will be released to the public we will have a clear picture of the exact number of babies that were killed. But the proofs that babies were killed are irrefutable.
In addition to murdering babies, Hamas has also taken several kids and babies hostages. The youngest is Kfir Bibs, only 9 mounth old.