Configurable Cascading / Custom. Needed values are Assign:Cascade All & Delete:Remove Link. First requirement says associated records/parts need to be updated, so cascade makes sense. Deletion doesn't say 'prevent delete' so it's not restrict delete, remove link is the right choice.
Reference:
https://docs.microsoft.com/en-us/dynamics365/customerengagement/on-
premises/customize/create-and-edit-1n-relationships?view=op-9-1