Among those Orthodox Jews who believe in reincarnation do they believe that reincarnation only is for those who have never had a probation? By probation I mean testing and trials of this earthly life and our ability to reason right from wrong and the power of freewill. This would exclude children who died, aborted babies, mentally handicapped and rest who don’t know their right hand from their left. So for people like these who are deprived of the privilege of reason and freewill like children and so on is reincarnation only for them so they can go through probation to make them ready for the glories of the afterlife?
Definitely not. There are many who "didn't get it right" the first time and didn't destine their fate properly. Most of them (except really evil people) are granted another chance (even many more times) until they improve their free will and meet the challenges of life in this world. Only afterwards will they benefit and enjoy the spiritual world-to-come. Yet again, everyone agrees with the Rambam that it's much more important to focus on improving ourselves in this world rather than thinking about future worlds or future lives.