Coconut oil is very light... they even have a extra virgin one I heard. So it doesn't really way your hair down unless you use too much. For my hair, I use a dime size amount and run it thru my hair, focusing on the ends.
Also, when you are stretching your relaxer, since the hair up top is starting to puff out (for lack of better words), the hair down low is thinner looking in constrast. Once you get your fresh relaxer you will notice a difference, as I did.
See the difference in the look of my ends after a relaxer... I though they were thin because they looked thin in comparison. But they really weren't.
Like I said, only chop if you have slip ends. If you ends are okay, then there's no need to chop. There's something called the search and destroy method were if you see a split, then you chop that one off without having to cut your whole hair.
As far as you using the Olive oil oil sheen, thats not substitute for a moisturizer. When adding a moisturizer the 1st ingredient should be water. So yeah you're adding that, but you still aren't moisturizing. Secondly, I've heard of some ladies just using something like the olive oil and water mixture you described, but I don't know 1st hand because I don't. If you don't want to be weighed down too much, I'd say use a liquid leave in. a good one for my is Elasta QP H-Two or Sunsilk Therma Shine Detagler spray. Use it on wet hair after you deep condish but don't over saturate. Seal with a little coconut oil or your olive oil and continue with your regime. I'm telling you, you are worrying about your ends when they look great!
RULE OF THUMB: if they ain't split, don't cut unless you want to for a certain styling purpose.