Precise and fast measurement of transverse beam properties is essential for understanding and optimizing particle beams. In this study, a multi-diagnostic approach is employed for high-dimensional transverse phase space reconstruction of high-intensity ion beams. This includes conventional single-slit scanning and the standard pepper-pot technique. In addition to these methods, a novel diagnostic tool called the Virtual Pepper-Pot (VPP), has been developed and implemented for the first time in high-intensity ion beam diagnostics to improve measurement constraints. The design, installation, and measurement of both 2D and 4D phase space distributions are carried out using these diagnostics. Benchmarking and validation studies of rms beam quantities, coupling parameters, and full 4D phase space distributions demonstrate strong agreement between the VPP and conventional pepper-pot methods. The results show that the VPP diagnostic technique offers high spatial resolution with fast and consistent measurement performance, establishing it as a reliable and effective alternative to traditional pepper-pot and slit-based techniques for complete 4D beam characterization.