Hello,
I'm currently using Houdini 16.5.536 (Game Tools version 1.30), Unreal Engine 4.20.1 and building for iOS 11.4.1.
As a test I took a grid and added a sine wave to it in houdini.
Which works fine in the editor but when I launch it onto my phone it looks like this
I've taken a look at the examples given at GDC 2017 to make sure I had the correct import settings for the picture files. I've also added the hip file, just in case.