Complex sentence: Lindsay and Crouse altered the story so that Maria was governess to all of the children, whose names and ages were changed, as was Maria's original surname (the show used "Rainer" instead of "Kutschera").
Split into simpler sentences: Lindsay and Crouse altered the story so that Maria was governess to all of them. The names and ages of the children were also altered, as was Maria's original surname (the show used "Rainer" instead of "Kutschera").