Angular 1 to React Port - Koan Stack

Refactor a private implementation of [login to view URL] to use react instead of Angular 1. Interested in proposals including nextjs or alternatives. Would like to hear arguments for and against an opinionated framework like nextjs vs just rolling your own implementation. This project's ideal candidate is someone who is an expert in React but competent in mongo, node, angular 1, and koa. If you submit your proposal as a business please provide how much developer(s) on the project will be paid who work on the project.