That's it. FCPX took only had the last keyframe which was 0% scale. Unpublishing Scale and all others in Motion made it work. It does now what I wanted – Build In and Build Out can be turned on and off – Changing the length of the clip in FCPX affects the middle part while "In" and "Out" remain the same length and speed. Excellent.
https://vimeo.com/338847744
That TEXT checkbox probably came when publishing the Text field in the Info > Text > Format tab.
"Schattenwurf" is drop shadow. Two "Stil" boxes – idk, I was trying out and publishing potentially useful things.
I had all these published because I want to be able to tweak them in FCPX as needed. I did not know that Text was available regardless of publishing it in Motion. My goal is to have text animation matching the music. Controlling the speed curve (in the keyframe editor) is rather important here which is limited in FCPX. In the end I wanted do do as much as possible in FCPX. My thought was to have as many controls as possible published so I can edit it as needed – since most of the final video will be animated text with music.
Thank you for your help, I really appreciate and I'm thankful for any advice. There is still a long way to go. Text glow, drop shadows and letter spacing movement is on my list. There are some good ones in the Motion library but some I'll have to build myself. I'll have to figure out the best workflow.
As an example this is an item from the mood board (text movement, glow and shadow). That's roughly the style I'm going for:
https://www.youtube.com/watch?v=nBllEp000B4