Somehow I do not think you'll get any answer to that from Airnav, they have made it clear that answer will not be given, or at least not until much closer to a release date, which again no one knows and could be months away if not a year.
But a little answer from me, you can get Mlat on PlanePlotter when using the Radarbox, what you can't get is Free Service as Radarbox can't be a Ground Station. so you can pay (think its £12) per year to obtain Mlat that is supplied by others PP members boxes that are capable mlat boxes.
Also unless I read one of Airnav's post wrong, their Mlat solution will be for their network only, how this will work on third party networks (if at all) would be totally unclear until its release.
I'm sad that Airnav can't just put peoples minds at reset and give a little detail, that may stop all the speculation, questions and issues arising from the unclear position they have created by saying this will come, but nothing else! I'm sure a simple statement could be made that does not give competitors any advantages, since three of them already provide mlat !
So don't expect any answer that answers you questions !