Hi Mike G.,
thank you very much for your support request.
1. Does UMotion – Professional fully work with Unity 2017 and 2018?
2. Can I use this to animate 2d characters? Sprites?
UMotion is mainly designed for animating 3D characters. But if your 2D character is already rigged and has some bones, you should be able to animate those transforms. I would recommend that you try the free UMotion Community and see if that works for you, I've honestly haven't tried using UMotion on 2D characters as of yet.
3. How does this differ than Final IK?
UMotion is an animation editor like Blender, Maya,... integrated right inside Unity. It allows you to create animations right inside Unity and save them as *.anim files. Inverse Kinematics can be used to simplify creating the animation but is then baked into the *.anim file (thus producing no runtime CPU overhead).
Final IK is a runtime Inverse Kinematics solution used on top of existing animations to adjust them to ingame situations.
4. I assume the animations I make/author/create with this asset can be easily used in games like other animations? And it's compatible with mecanim?
UMotion produces *.anim files. You can use them in any of your Unity projects. Yes, they are fully compatible with Mecanim (and also with the legacy animation system).
5. Is this setup where I have a starting point for the model and an ending point and the asset figures out the movements in between?
Yes, UMotion interpolates between two poses. If you for example define a pose on frame 0 and a different pose on frame 10, then you get a smooth interpolation in between.
6. Does this asset come with any animations?
It comes with a sample scene and 4 sample animations. There purpose is more to demonstrate how UMotion works and not that much designed for in-game use. But if you need animations for in game use, there are a lot of free (motion captured) animations on the asset store that you can use (e.g. Raw Mocap Data For Mecanim).
7. Can it animate non-humanoid models? Like a 4 legged creature or an 8 legged machine?
Yes you can animate any type of 3D model (e.g. Guns, Creatures, Doors, Machines,...).
Let me know if you have any further questions.