I’m a bit late on the reply but i would still like to show you how to do it. For this guide i’ve designed a replica model and will go through the steps on how to import it into Studio with texture.
The store page mentions that all house models are textured with a 128x128 color scheme. Usually this is a series of flat colored pixels. I myself will be using a baked texture, but this should not affect the following steps.
Step 1: Ensure that your engine is set to Blender Render (Cycles and Eevee currently do not support this process). Make sure that the color scheme texture file is present in Blender. You can check this in the UV/Image Editor.
Step 2: Remove all materials present on the model and create a new material.
Step 3: Head over to the Texture tab, go to the Material Texture category and select your image texture.
Step 4: Export the .fbx like you normally would.
Step 5: Congratulations, you finished the guide! 
