I reached out to CTBUH and heard back that "Republication of our data for commercial use in not allowed." and they did not provide a waiver to this, therefore on this basis the data is incompatible with OSM. We'll need to go through and remove all instances where you copied this data previously, and please going forward don't use their data as a source.

For building heights i would recommend other sources like compatible LIDAR data, a physical survey, or photogrametry.