AWS Serverless Web App with External API Integration

We're building a family of web apps, both customer and internal facing, that help us digitalize our processes. I'm looking for a well-rounded developer or team that is comfortable with serverless development on AWS (S3/Lambda/Cognito) as well as integrating with APIs. Our existing web app is built on the AWS serverless platform plus a relatively common stack that includes and Node.js, Vue.js. Mimicking this architecture is preferred. [As for database architecture, we are looking for a recommendation on which platform to use, whether that is built on RDS or DynamoDB] As far as APIs, some are common, such as integrating Zendesk's Web Widget. However, we are also looking to integrate with a lesser known Taiwan-based ERP called NEO. We can provide the API guide in English. You will be working closely with our internal developer, who will be responsible for maintaining the application into the future. I have laid out the functions in a user story map, an Adobe XD prototype, narrated walkthrough videos, and have associated video and screenshot segments with each function. We will also provide a draft of the database schema. Finally, as the timing is extremely important, a phased approach may become necessary. We are open to negotiating the scope within this first period. We prefer multiple deliverables tied to multiple payments, and the option to continue working together after this first phase.