I'm not sure Unreal supports Animations that are not bone driven. The easiest thing to do would be creating a small box as b_root, linking the other object to it. Make a Snapshot of the Object on Frame 0 and skin it to these two bones (with no influences of b_Root). Keep in mind to enable Bone Translation in the AnimSet.
First: Export your main weighted mesh as an FBX, without animation. Import this as your skeletal mesh. (make sure animations are not checked on this export) Next: export your animations to Fbx files. I believe one file per sequence, as there is no internal sequence delimiting or import options that I have found. Make sure…