Groupman BJJ Clone with Messaging

I need a faithful replica of the Groupman BJJ mobile app, keeping its overall look, navigation flow, and user experience intact while adding three key improvements: in-app messaging, integrated emailing, and real-time push notifications. The finished product must run smoothly on both iOS and Android; feel free to recommend the stack you’re most comfortable with—whether React Native, Flutter, Kotlin/Swift, or another solid cross-platform approach—so long as the interface remains visually consistent with the original app.

To make expectations crystal clear, here’s what I’ll be looking for at hand-off:
• Complete iOS and Android builds ready for submission to the App Store and Google Play
• Source code and any supporting backend or API documentation required for messaging, email delivery, and push notification services
• A quick walk-through (video or live call) showing those three new features working on real devices and in the respective app stores’ test environments

If you have shipped comparable social or sports-community apps before, especially ones that use Firebase, OneSignal, or similar notification/email providers, that experience will be a plus. I value clean code, timely communication, and clear documentation, and I’m happy to answer any questions you need clarified before we get started.