Magento-1 to Magento-2 Migration

Existing installation is multi store, multi lingual Magento CE 1.9 with Ultimo theme and many extensions and customization. This is not a classic migration. It will be a fresh Magento 2.x installation with preferably Porto theme. We need to discuss first what functionality will be implemented and how in the new Magento 2.x Then products and customers will be imported. Key requirement is the absolute minimum number of extensions and custom code. There are 4 stores in existing Magento 1.9 The developer must have implemented M1 to M2 successful migrations in the past and be Magento certified.