I personally don't think she can change the speed of the object she teleports. That would be too hax and be even more powerful than Accelerator since she can teleport them before changing the vectors. I can agree with the changes in position and orientation, but speed is another thing.

About the inconsistencies about her powers (like the needles piercing the ground and the like), I think they are exactly that - inconsistencies. Either it simply looks cooler so the animators did it that way, or they simply neglected or couldn't care less about realism (rightfully so since this is sci-fi/fantasy).