Manoxik

Hi, you have to check data in GIS software. TB is not GIS tool and it can export wrong shape coordinates. Download QGIS and try import all your data into it. It looks like data aren't on the same place.

Heightmap ASC is text format, you can edit values directly in file. SHP you can edit coordinates with GIS tool transformation

No, but you can vectorize surface mask. Nope, Terrain Processor and Terrain Processor support only asc heightmap. You can use GIS to save GeoTIFF as asc

I think you have different coordinates for heightmap and shp. You can check this in GIS (QGIS).