VooCAT is a motion-tracking package which works with Blender. I haven't tried it. It's only a hundred Euros.
The "non-commercial" version is Voodoo Camera Tracker. But to use it with a modern version of Blender you need this import script (the instructions for installing are here).
My goal with the above paragraph was to bore you until you cried. Did it work?
Here's how to tell FCP what track to paste into.
Allan Mackey reminded us (in the comments below) about Trello. So I'm working in Trello to schedule. I'll tell you how that goes.