Magento 1 to Magento 2 Migration

We are looking for the following Objectives: Current Configuration 5 domains on Magento 1.8-1.9.x Combined ~300,000 skus Combined ~20000 orders Combined ~8000 customers All separate install of Magento (no multi store setup) Each site has it’s own [login to view URL] payment gateway and PayPal All sites have simple and configurable products only (no bundle, downloadable, etc.) All sites have custom options on Catalog, Search products Catalog, Search products have tier pricing (not all, but some) One site has special customer groups (One site has Designer 1 and Designer 2 customer groups) That site has specific pricing for those groups, but we can redo this very easily All other sites have standard built in customer groups and do not have pricing for those specific groups There are extensions across the sites but each site does not have the exact same extensions Our databases are very large and might be corrupt, at the very least bloated due to years of developers being in there and lots of extensions being installed/uninstalled Expected New Configuration Single fresh install of Magento 2.<latest version> All domains/stores transferred new to Magento 2.1 as a multi store single install Each domain should have its own theme (which we have found already and will purchase) Each domain should have its own payment gateway (we have separate [login to view URL] accounts for each site) Looking not to have databases migrated or moved over, looking for products to be injected as if they were new products to remove bloat or any unwanted corruption in the current database to transfer Our databases may be corrupt and very bloated We will install extensions fresh so we don’t want those migrating This is done to only keep essential extensions