ApiController vs ODataController when exposing DTOs

I think the issue was by ths following , To be RESTful you don't necessarily have to return the full representation of the resource You do however want to enable hypermedia as means to get/set all the information the user of your API needs (Hypermedia as the engine of application state - a.k.a. HATEOAS)
To satisfy that you can either use the suggestion by @bowmanb to put a URI for all the locations or add individual URIs for each of the locations. You probably want to add additional URIs for other options of doing something with the resource.

fixed the issue. Will look into that further Actually I got it working the way I wanted, more or less, by using OWIN and writing my own middleware.
Basically I wanted a way to force a content-type without having to write a specific oData formatter for each instance. So oData could continue to format whichever way it was told to, and I would just tell the browser to treat it as plain text (or whatever else I wanted it to be).

public class OWINCustomMiddleware : OwinMiddleware {

  public OWINCustomMiddleware(OwinMiddleware next): base(next) {
  }

  public async override Task Invoke(IOwinContext context) {

  //Check if a content-type coercion querystring token is present
    if (context.Request.QueryString.HasValue) {
      NameValueCollection queryString = HttpUtility.ParseQueryString(context.Request.QueryString.Value);
      String coerce = queryString.Get("$coerce");
      if (!String.IsNullOrWhiteSpace(coerce)) {
      //Remove $coerce token so it doesn't impact future methods
        queryString.Remove("$coerce");
        context.Request.QueryString = new QueryString(queryString.ToString());
      //Append a header to the request, to be later used in Response Content-Type coercion
        context.Request.Headers.Add("coerce", new String[] { coerce });
      }
    }

    await Next.Invoke(context);

  //Coerce existing response content-type to value of coerce header (if present)
    if (context.Request.Headers != null) {
      if (context.Request.Headers["coerce"] != null) {
        Int32 index = context.Response.ContentType.IndexOf(';');
        if (index > 0) {
          context.Response.ContentType = context.Request.Headers["coerce"] + context.Response.ContentType.Substring(index, context.Response.ContentType.Length - index);
        } else {
          context.Response.ContentType = context.Request.Headers["coerce"];
        }
      }
    }

  }
}

This might help you It seems the REST consensus is that when updating using PUT, one supplies the entire entity to replace.
Programmatically, it would work having PUT /person/{id} accepting input which behind the scenes maps to UpdatePersonDTO instead of Person.

With these it helps First, from the namespace System.Web.OData.ODataController, I think you are using the Web API OData V4 library. V4 doesn't accept application/atomsvc+xml because only "Json" is the standard in OData V4 spec.
Second, odata=fullmetadata is the OData V3 metadata header, for V4, it should be odata.metadata=full