set hr=##class(%Net.HttpRequest).%New()
  set hr.Server = "server.com"
  set hr.Location = "method"
  do hr.InsertParam("name","value")
  do hr.InsertParam("name2","value2")
  do hr.Post("",1)

And the result

USER>do ^test
POST /method?name=value&name2=value2 HTTP/1.1
User-Agent: Mozilla/4.0 (compatible; InterSystems IRIS;)
Host: server.com
Accept-Encoding: gzip
Content-Length: 0

Yeah, of course, you can change any class, if it's not a system and not deployed class stored in a read-only database

looks like you already know how to generate classes, so, to edit some method, you have to open a particular method by its id, which can be constructed from the class name and the method name.

USER>set method = ##class(%Dictionary.MethodDefinition).%OpenId("%Library.File||Exists") 

USER>write method.Implementation.Size
56

Well, Axure, is just a prototyping tool. And it does not have anything that would help to create something production-ready, with any kind of backend at all. It would be probably ok for designers to create some prototype of the application, or probably make something working, but only if no database is needed at all, such as a landing page.

So, I don't think that this tool could be considered in this role

The most important thing you have to understand first, that when you use containers-way for running your application (and Docker here is just one of the ways, to run containers). You have to remember, that container should be as simple as possible, and do just only one thing. So, it means, that your NodeJS application, should run in a separate container, even if it connects to IRIS, it still has to be run separately and connected to IRIS over TCP. 

So, you can use any official Debian-based NodeJS image, put InterSystems NodeJS driver in it, as well as your application, and run it. And your IRIS will run in a separate container, no matter which version.