Some possible code improvements:

1. Instead of:

s sc = httprequest.Post("http://127.0.0.1:57772/api/v0/bwxpert/visiocheck/account")

it's enough to specify:

s sc = httprequest.Post("/api/v0/bwxpert/visiocheck/account")

as the rest of the address is defined beforehand.

2. Instead of:

s httprequest.Authorization = "Basic X1N5c3RlbTpTWVM="

you can specify:

s httprequest.Username = "_SYSTEM"
s httprequest.Password = "SYS"

Which is more readable

3. When specifying server, protocol in not required, incorrect even:

s httprequest.Server="127.0.0.1"

4. Finally, don't use short syntax (s, d) and use one naming convention consistently - in your example some commands are in lowercase and some start with a capital letter.

Private is not important in that case - it only affects from where method could be called. Private methods can be invoked only by methods of this class or its subclasses.

The difference between class methods and instance methods is that instance methods can access object context. For example you can access current object property from instance methods. Use instance methods only when you need access to object context. In all other cases use class methods.

Here's a sample code, highlighting the difference:

Class Test.Person Extends %RegisteredObject {

Property Name As %String;

Method PrintName() {
  Write ..Name
}

ClassMethod PrintText(text) {
  Write text
}

}

What's your version?

To pinpoint the error, please:

1. Create app /csp/test with the same broker
2. Restart Caché and IIS

After that try to open:

1. SMP: http://localhost/csp/sys/%25CSP.Portal.Home.zen
2. Your old app: http:// localhost/myapi/check
3. Your new app: http:// localhost/csp/test/check

Store $lb maybe? Or is there some drawbacks?

%ZEN.Auxiliary.jsonProvider is available since 2009.2. You'll need to upgrade.

1. Please ask this as a separate question.
2. What, and from where do you want to kill? Why? Consider expanding your question.

and by the way, is Set Request.Https=1 correct given that Set Request.Https=$$$YES not supported in Ensemble 2014?

Yes, it's the same thing $$$YES macro resolves into 1.

but I get this error :  
{"Errors":["The request entity's media type 'text/html' is not supported for this resource."],"StatusCode":415}

Specify content type. For example:

Set Request.ContentType = "application/json"

or whatever content type the api requires.

so is there a way to get it working with SSLConfig

As I said:

Where  SSLConfiguration is the name of your ssl config.

You need to create a SSL config. Docs explain how.

 test 0 or 1 means as the doc doesn't mention it!?

Test values

• 0 - send as usual
• 1 - do not send, output request to the current device
• 2- send the request and output response to the current device

location in Post method is optional given that we set Set Request.Location = "/STP_IF/rest/Employee/Create"? 

Yes, it's enough to specify Location property.

I'd move

Write !?(%lev*3)

into a separate method:

ClassMethod Log(text)
{
  Write !?(%lev*3), text
}

Use static classmethods, unless you need them to be instance methods.

SET JArray=["somthing "] 

OR

Set Array1 = ##class(%Library.DynamicArray).%New()
 SET Array1=[]

so in both cases Array1 or JArray is not understanding [] so should be including or extending a classe(s) or ...etc 

That's available from version 2016.2. Refer to your local documentation or online documentation for 2014 version.

FYI Srever name & port are not required for this Wed Service. 

It's not server name - it's host and it's required. You also need to specify HTTPS and SSLConfig.

If I execute your code in test mode (  Set Status = Request.Post(,1) ) I receive:

POST /https%3A//devtest.altus.net.au/STP_IF/rest/Employee/ HTTP/1.1
User-Agent: Mozilla/4.0 (compatible; Cache;)
Host: localhost
Accept-Encoding: gzip
Content-Length: 239
Content-Type: text/html; charset=UTF-8
 
{
        "Id":123,
        "PayerAustralianBusinessNumbe":"PayerAustralianBusinessNumbe",
        "PayerBusinessHoursPhoneNumbe":"PayerBusinessHoursPhoneNumbe",
        "PayerEmailAddress":"email",
        "PayerWithholdingPayerNumber":"PayerWithholdingPayerNumber"
}

You should probably modify your code like this this:

ClassMethod Test(test As %String(VALUELIST="0,1,2") = 1)
{
 Set Body = ##class(%ZEN.proxyObject).%New()
 Set Body.Id = "123"
 Set Body.PayerEmailAddress = "email"
 Set Body.PayerBusinessHoursPhoneNumbe = "PayerBusinessHoursPhoneNumbe"
 Set Body.PayerAustralianBusinessNumbe = "PayerAustralianBusinessNumbe"
 Set Body.PayerWithholdingPayerNumber = "PayerWithholdingPayerNumber"

 Set Request= ##class(%Net.HttpRequest).%New()
 Set Request.Server = "devtest.altus.net.au"
 
 Set Request.Location = "STP_IF/rest/Employee/"
 Set Request.Https = $$$YES
 Set Request.SSLConfiguration = "YourSSLConfig"
 Set Status = ##class(%ZEN.Auxiliary.jsonProvider).%WriteJSONStreamFromObject(Request.EntityBody, Body)
 Set Status = Request.Post(,test)
}

Where  SSLConfiguration is the name of your ssl config. Afterwards with test=1 I get this:

POST /STP_IF/rest/Employee/ HTTP/1.1
User-Agent: Mozilla/4.0 (compatible; Cache;)
Host: devtest.altus.net.au
Accept-Encoding: gzip
Content-Length: 239
Content-Type: text/html; charset=UTF-8
 
{
        "Id":123,
        "PayerAustralianBusinessNumbe":"PayerAustralianBusinessNumbe",
        "PayerBusinessHoursPhoneNumbe":"PayerBusinessHoursPhoneNumbe",
        "PayerEmailAddress":"email",
        "PayerWithholdingPayerNumber":"PayerWithholdingPayerNumber"
}

And the response with test=2 is as follows:

HTTP/1.1 405 Method Not Allowed
ALLOW: GET
CACHE-CONTROL: no-cache
CONNECTION: keep-alive
CONTENT-LENGTH: 73
CONTENT-TYPE: application/json; charset=utf-8
DATE: Fri, 05 Jan 2018 08:16:20 GMT
EXPIRES: -1
PRAGMA: no-cache
SERVER: Microsoft-IIS/8.5
 
{"Message":"The requested resource does not support http method 'POST'."}

You should check the API docs for correct location (or HTTP verb)

I'm basically looking to handcraft the Body.%ToJSON() content to to be contained in []

Wrap Body in %ListOfObjects for that:

Set List = ##class(%ListOfObjects).%New()
Do List.Insert(Body)
Set Status = ##class(%ZEN.Auxiliary.jsonProvider).%WriteJSONStreamFromObject(Request.EntityBody, List)

And your request body would look like this:

[ {
                "Id":123,
                "PayerAustralianBusinessNumbe":"PayerAustralianBusinessNumbe",
                "PayerBusinessHoursPhoneNumbe":"PayerBusinessHoursPhoneNumbe",
                "PayerEmailAddress":"email",
                "PayerWithholdingPayerNumber":"PayerWithholdingPayerNumber"
        }
]

Why not?

It's an oref, you can even get the object by this string if it exists somewhere in process memory, here's an example.

passing sbJSON by reference would make this recursive construct easier to understand

Object are always passed by reference.

replacement with %ToJSON()  does it as well.

Is there a way to call %ToJSON, so it would return formatted output?

Export it as XML. Store in VCS with code. Import with the rest of the code.

Other option is to store it as XData, here's sample code:

XData DisplayProperies
{
<Export generator="Cache">
<Global>
<Node><Sub>^Test</Sub>
<Node><Sub>1</Sub>
<Data>123</Data>
</Node>
<Node><Sub>Val2</Sub>
<Data>prop3</Data>
</Node>
<Node><Sub></Sub>
<Data>prop1</Data>
</Node>
</Node>
</Global>
</Export>
}

/// Set global
/// do ##class(Class.Installer).setGlobal()
ClassMethod setGlobal() As %Status
{
    #dim sc As %Status = $$$OK
    #dim className As %String = $classname()
    
    // search for XData: DisplayProperies
    #dim xdata As %Dictionary.CompiledXData = ##class(%Dictionary.CompiledXData).IDKEYOpen(className, "DisplayProperies",, .sc)
    quit:$$$ISERR(sc) sc

    set stream = xdata.Data
    set sc = $system.OBJ.LoadStream(stream, "/displaylog=0 /displayerror=0")
    quit sc
}