Complete Shopify Store Setup

I need one partner to take my new Shopify build from blank canvas to sales-ready. Everything will run on the Stiletto theme, but the default look and feel won’t cut it—I want a polished experience that mirrors Sephora-style category and filter behaviour and looks flawless on mobile.

Core scope
• Configure the store from scratch, connecting it to the necessary Shopify APIs.
• Custom-tailor the Stiletto theme—layout tweaks, brand-driven styling, and added functionality—without sacrificing update compatibility.
• Reproduce advanced category and filter logic (think Sephora.com) so shoppers can drill down effortlessly.
• Build product pages that pull rich data from metafields, displayed in neatly organised tabs.
• Migrate only the customer records from my existing CS-Cart shop.
• Hook up logistics integrations for my chosen couriers so fulfilment data flows automatically.
• Implement payments and marketing apps, with Klarna checkout and Klaviyo flows fully operational.

Acceptance criteria
1. Store launches with no console errors and passes Shopify’s speed report on mobile.
2. Filters return correct in-stock results across all collections.
3. All migrated customers can log in and see their order history.
4. Test orders reach couriers’ dashboards and trigger Klaviyo confirmation emails.
5. Theme changes remain editable through the Stiletto customiser; no core files overwritten.

Please outline your approach to the API work, previous Stiletto (or similar) custom builds, and an estimated timeline for each milestone when you reply.