@ Sure, you can do that with dungeon event listeners. After DA generates the layout and emit markers, you hook into the OnMarkersEmitted blueprint function. Then take each of the markers, and clamp them on the landscape (or you landscape mesh). This can be done with a line trace to see where it collides to find the Z on the XY position and move the marker along Z. Then those markers are sent to the theming engine and they places your buildings correctly on the landscape.
Let me know if you need a working sample