I don't see an "extension" of the Troy area. First because of the parking lot which would have to be removed. Besides the mentioned fact that it is useful for winter operations (I assume they will be using the old entrance then), the second and more important reason is simple: I think it is just not necessary.
This short article of 2016 gives a glimpse into the long term expansion plans up to ~2026:
https://www.themepark-central.de/neuer-eingang-und-45-m-hoher-turm-fuer-das-toverland/
Althoug it is in german you can take a look at the linked area map, wich is said to be an excerpt of the planning process with the local authority:
https://www.themepark-central.de/wp-content/uploads/2016/06/Toverland_Erweiterung.jpg
It depicts the current park and areas seemingly available for expansion. You can spot Port Laguna in dark blue, the new parking area in orange to the left of the pathway (the bottom quarter is the current Bus parking lot) and Avalon in yellow. Note that the upper third of the Avalon expansion area is covered by a see (behind the "current" accessible area - I assume it is serving as a reservoir for the themed water areas in Avalon). Behind that sea would be the Hotel/Resort area (green).
The mindful reader will immediately spot the two additional areas in red and light blue. They too are presumably available for themed areas with attractions. If you compare the dimensions, you can get an impression of the incredibly suitable spot on earth Toverland has secured themselves.
And BTW you can see the important role of Port Laguna in the future. It may get the very central hub of the park.
At the end this leads back to my point one. Considering these great options, they just won't shut down any available parking space. They are about to need it if plans are progressing well. And I hope they will! If the current expansion phase succeeds, we might look at a well growing park, probably "closing the gap" to premier parks like Efteling and Phantasialand in the vicinity. Or maybe even leaving them behind.