Data Transformation Pipeline for Analytics Integration

I need to design a data transformation pipeline that extracts data from multiple sources, transforms it, and loads it into our analytics platform. The sources include: 1) A PostgreSQL database with customer and transaction data, 2) Salesforce API for CRM data, 3) Google Analytics for website behavior, and 4) CSV files with marketing campaign information. The pipeline should: merge customer identities across platforms, clean and standardize address and contact information, calculate derived metrics (customer lifetime value, conversion rates, etc.), aggregate data for different time periods, and structure everything for optimal querying in our analytics dashboard. Please provide a detailed pipeline design including recommended tools (open-source preferred), transformation logic, data validation steps, error handling processes, and scheduling considerations. Also address data privacy concerns and suggest an incremental loading approach to minimize processing time.