Hooking up AWS Amplify auth (using Cognito under the covers) allowed me to get signup/verify/login elements built pretty quickly, although I made the mistake of assuming the sign up promise would resolve to something meaningful (like a Cognito user) but instead it gives 'SUCCESS'.

Here's my commit realizing that:  https://github.com/jrnewton/tapedeck-client/commit/fa0a334e060ad83361ce9855e10e9f4388783ee0

Here are the related issues:
https://github.com/aws-amplify/amplify-js/issues/2562
https://github.com/aws-amplify/amplify-js/issues/6320