Step-Parents and Stolen Inheritances

Working on a story for both and on the issue of warring stepfamilies after the main breadwinner passes, and step-spouses try to step and grab the lions share of the estate away from children and grandchildren. How can this issue be alleviated? What should a breadwinner do to minimize a protracted and costly court battle? What rights do kids have in a step-parent estate battle? What right does the step-parent have (data shows it’s almost always a stepmother involved. All comments welcome. Requirements: Estate planning experts, family finances experts, money management experts, legal experts, actual step-parens and family members who have fought for estate cash – and won or lost.