Hi, if it's the same file, PixelOver has a system of synchronization that's to say if the file is modified in an external program it will be resynchronized in PixelOver.
But for the animations if new ones have been added there will be one more step, you will need to create a new animation in PixelOver and you select the object in the bottom left panel under the animation input choose the right animation and add a key. (It's a bit complicated so I'll add a short gif here to better explain later)
And for the moment there is no way to only import animations to another imported 3d model. But in the future animation system will be improved.