Honeycomb,
Split ends and uneven ends are NOT the same. You can have uneven ends which are also split, but not necesarily. You can get a bad haircut and have uneven ends. When you think of split ends, think "frayed." You can often look at one up close and see the portion which is split...solid to a point and then for lack of a better word, several forks in the road. You might also refer to some of the previous threads on how specific people here "know or recognize" their own split ends.
Your questions: Do uneven ends have to be clipped to maintain length? Do you think even hair grows faster? NO, to both. Think about it. A lot of people who have layers grow out hair over time and then get to a point when they start doing evening all around, but not necessarily at the beginning.
Hope this helps...
Jade