I suppose it goes by contest. I would think that the meteor spell would outdo Kelvin's simple spells, but likely would lose out to his advanced spell. (However, he can't really walk around with his advanced...) On the other hand, lightning step is literal teleportation, so in shorter bursts, it should defeat the meteor spell. On the other hand, lightning step takes a lot of energy when used consecutively, despite being actual teleportation. Also, you cannot hit someone while not physically there, so lightning step is not as useful for attack as much as dodging defense. Granted, using it to get behind people or coming straight out of it with a bolt of lightning probably is very effective against most characters.
Then there is the velocity blade. I am not quite sure where to place this one, but mentally I have the running speed it gives on par with Kelvins accelerate spell, which would make it slower than meteor as far as running goes. However, as far as swinging the blade, as that character has yet to do combat with it I have no idea.
Hope you enjoyed my hazy and probably slightly irrational reasoning on the matter :D