Multi-storefront on each, feasibility?
Map what each storefront must share: catalog, prices, company records, inventory, accounts and staff permissions. Confirm the scope provided by the proposed BigCommerce plan and B2B setup, then test any needed synchronization. For Magento Open Source and Adobe Commerce PaaS, verify website, store and view configuration; assess Adobe SaaS separately. A multi-storefront label alone does not prove that the pricing, checkout or customer-data boundaries match your business.
Official references: BigCommerce B2B Edition; Adobe scope hierarchy; Adobe deployment models.