Comprehensive Web & Mobile Application Development

As someone who's seeking an effective and diverse Web and Mobile application system, I have specific requirements:

- Website: The primary role of the website is to act as a management web system where the majority of the business operations will be conducted.

- Functionalities: Crucial functionalities needed include User Management and Data Analytics. With user management, it's intended to track, analyze, and respond to user behavior. Accompanied by data analytics, it will assist in making informed decisions backed by user data.

- Mobile Application: This will be developed for both Android and iOS. It requires specific features such as User Authentication and Push Notifications. Additionally, I need my users to access a nutrition plan, workout plan, their profile, and their settings screen through the app.

Ideal Skills:
- Proven experience in web and mobile app development
- Proficient in iOS and Android development
- Proficiency in User Management interfaces and data analytics insights
- Knowledge of implementing user-focused design in mobile apps.

The envisioned system will consist of about 500 screens equally divided between mobile application and the management web system.