We know they'll be the same sex. We don't know if the behavior of the mammals is identical, or if they have the same thoughts. Nor do we know if they will develop identically or whether genetics alone determine the extent of individuality. To know, we'd must clone a human. The closest thing we have to a human clone are identical twins, the result of a fertilized egg dividing and forming into two separate embryos.
Identical twins have the same genetic make up.
Their physical appearance is identical. They are always the same sex. But identical twins are not the same person. They are separate individuals. They develop differently though most pairs are raised in the same environment.