Status: OUT
Factory Method and Singleton address distinct creational concerns that can be seen as complementary: Factory Method governs which type to instantiate (serving as a foundational creation-policy mechanism across multiple patterns), while Singleton governs how many instances exist and how they are accessed (providing controlled global access with lazy initialization and subclass flexibility). Together they illustrate how creational patterns can address both type selection and instance management.
Two ends of the creational spectrum — what to create vs how many may exist
Depends on (SL): factory-method-as-foundational-creational, singleton-controlled-global-access