The formal reference model for software requirements must be useful for specification of mappings from both functional and non-functional requirements. The topological functioning model (TFM) can serve as such reference model for specifying mappings from software requirements to functional characteristics and structure of the modeled system. Different types of mapping of functional requirements and their aspects such as completeness and overlapping have mathematical background and can be described using mathematical constructs (the inclusion predicate, disjoint predicate, covering predicate, projection, and separation family of functions), as well as meta-classes in the metamodel. This paper continues the previous work and illustrates the way how specification of the TFM functional characteristics and causal relationships can be extended and can represent mappings from the requirements as tuples of TFM functional features extended with requirements sets and mapping characteristics, namely, completeness and overlapping for functional requirements, and, additionally, scope and dynamic characteristics for non-functional ones. This allows formal tracing from the whole set of requirements to software implementing constructs via TFM elements and vice versa, that could be useful for further architectural decisions and development of test cases.