This paper addresses the challenge of improving the connections between products, manufacturers, and suppliers to increase the efficiency and resilience of global supply chains. We highlight the challenges of existing approaches in capturing the rich multimodal data of complex capabilities, certifications, geographical constraints, and real-world manufacturer profiles. We present PMGraph, a publicly available benchmark for bimodal and heterogeneous multimodal supply chain graphs encompassing 8,888 manufacturers, over 70,000 products, over 110,000 manufacturer-product links, and over 29,000 product images. Building on this, we propose Cascade Multimodal Attributed Graph (C-MAG), a two-stage architecture that aligns and aggregates textual and visual attributes into intermediate group embeddings, then propagates the manufacturer-product heterogeneous graph through multiscale message passing to improve link prediction accuracy. C-MAG also provides practical guidance on modality-aware fusion that maintains prediction performance in the presence of real-world noise.