In response to the challenges associated with fault recovery in islanded distribution networks under total blackout conditions—particularly in remote regions abundant in hydropower and solar energy resources—this study proposes a black start strategy leveraging the coordinated operation of small hydropower plants, distributed photovoltaics (PV), and grid-forming energy storage systems (GFESS). A hierarchical startup framework is developed by analyzing the black start capabilities of run-of-river and reservoir-based small hydropower, distributed PV, and GFESS. The system restoration process is formulated as a mixed-integer second-order cone programming (MISOCP) model, which introduces multiple types of power constraints such as power balance, network topology, and equipment startup, as well as computational constraints such as radial structure and single commodity flow, to ensure system connectivity and operational reliability. A case study based on the IEEE 33-bus distribution system is conducted using the commercial solver GUROBI. The results demonstrate that the proposed strategy enables sequential load restoration with stable frequency and voltage profiles, achieving a final restoration rate of 98.3%. Additionally, by modifying the number of lines restored at each stage, the method exhibits strong scalability and adaptability across varying operational scenarios.