Your system looks pretty good, something that Lionel should have done. Any plans to sell these?
The long and short of it is... Maybe. I've been busy with other projects and work lately, and haven't had the time to do a lot more work on this. At this time I'm also not happy with the cost involved to get a plug-and play unit running. It may still be feasible for someone that really wants to run their LC/+ from TMCC/Legacy, but a price tag in the $150-$200 range for a finished product is about twice what I originally was hoping for.
I will eventually be getting back to this project, and when I do I hope to build a couple test units to send out to folks to be tested out, then from there fix any problems that come up.
In the Spring of 2016 Jon Zahornacky was asked if Legacy will ever operate LC and LC+. He responded that it was unknown at that time.
As discussed in many other threads, Lionel could produce their own bridge device any time they wish to do so. I would expect that it has much more to do with marketing, a little to do with demand, and nothing to do with the ability to design such a thing.
With the introduction of the new Bluetooth LionChief App, I would be fairly disappointed if the iCab app is not updated at some point to allow it to also control Bluetooth enabled LC/+ engines, though I could see that not happening for the same marketing reasons that would discourage allowing control from a cab2.
JGL