Like I promised I prepared empty project template for Application Page with React App on SharePoint 2016.
Application page named MyReactApp.aspx is in Layouts/MySPAppPageReactApp mapped folder inside Visual Studio Solution.
React App for Application page is inside ReactApps/my-react-app subfolder of project root folder.
Deploy WSP on your SharePoint 2016 Server. Go to Application Page (URL: /_layouts/15/MySPAppPageReactApp/MyReactApp.aspx) and you can see “Welcome to React on SharePoint Application Page” text on it.
Go to React App inside ReactApps/my-react-app and run gulp command. Update client side code inside App.tsx file. When you save changes you can see updated Application Page.