The green transition is driving a rapid expansion of renewable energy sources (RESs) and electrified energy conversion pathways, requiring power grids to accommodate more power electronic-interfaced facilities and new forms of flexible demand. In this context, complex hybrid power plants (CHPPs) integrating RESs such as PV and wind, together with large-scale energy storage such as Power-to-X systems, are increasingly connected to the grid as power converter-dominated facilities. Under these conditions, harmonic emission, background distortion and grid-impedance interaction become central elements in grid-connection assessment and power-quality compliance. Harmonic compliance studies for CHPPs are often carried out through workflows that depend on case-specific modeling choices, manual configuration steps and undocumented assumptions regarding harmonic sources, aggregation and study setup. This can lead to limited transparency and weak reproducibility when models are transferred between stakeholders or when results are reviewed as part of compliance documentation. This paper develops a framework that structures the harmonic compliance assessment process from requirement capture to model configuration and acceptance testing in DIgSILENT PowerFactory. The framework is organized into two parts. First, a modeling guideline defines a systematic procedure for representing and parameterizing CHPP subsystems, including explicit documentation of input data, assumptions and plant-level aggregation choices, as well as consistent handling of harmonic source definitions and background harmonics. Second, a standardized test specification defines repeatable study cases that correspond to typical compliance needs, including load-flow consistency checks, harmonic load-flow analysis, background harmonic evaluation, frequency sweep studies and grid-impedance variation assessment. The verification logic is aligned with a structured development approach inspired by the V-model, where requirements are mapped to configuration activities and associated acceptance tests to support traceable validation of both the model and the study procedure. The work is validated through an industrially hybrid power plant including Power-to-Ammonia, Wind power - and PV production in Denmark. Using the available facility specifications, a reference plant model is recreated by following the requirements-driven framework and the defined test suite is executed on both the original and recreated models under identical study conditions. The comparison indicates close agreement across the main harmonic- and impedance-related study outputs, including consistent harmonic load-flow indicators and aligned frequency-domain impedance responses across the considered operating conditions and grid-impedance variations which demonstrates that the proposed framework supports systematic model recreation and consistent compliance-relevant results.