We use an API for this. Design a Single Endpoint API for the Calls you have to make, this API knows of the other microservices and routes the requests where ever you need them. Your frontend just talks to this API and nothing else. This way you can change what happens when the frontend needs something easily by changing your stuff in the API. Just see it as the gate your microservices cluster.

I guess that was your question, right?

Really depends on what micro service you are offering.

When you say "For every micro service there is backend", it is confusing as micro-services are backend services.

Your front end can be as simple as the AWS console. Get your users signed up and offer your services as an API or via a shell or however you were planning to give them.

For scaling, try using containers. Though it should not be a problem when you are starting out, you could just use a single large instance and take it from there.

Well, I think microservices is more for backend applications than frontend. But one nice way to handle microservices in frontend i think it's by components.

You can see and example in Angular and React, I think the best way is making a folder by component and have all the js, css and html in every folder, because when you don't need a component simply can delete de folder and remove the line in your code.