As an experienced Shopify Plus developer with over a decade in the industry, I've honed my skills precisely for projects like yours. Starting from Shopify to its every intricate detail of e-commerce friendliness, I understand how important it is to craft an immersive user interface, especially when customization is involved. From the given description of your project, it's clear that you need a WooCommerce plugin that not only allows image cropping but also dimensions calculation and material selection.
My expertise in CSS, HTML, PHP, and both WooCommerce and WordPress development will come in handy while creating a simplified UI for your customers to work smoothly through the customization process. Additionally, paying attention to admin panel requirements, I assure you that I will include all the necessary information like dimensions, cropped image and selected material on the order page.
Lastly, as an added perk from my side, I have considerable knowledge and experience in digital marketing strategies like Google Ads, Facebook Marketing and more. This could be useful when it comes to making your wall-mural e-commerce site more engaging with properly showcased catalogues via social media platforms. Let us differentiate your brand frrom others.