Based on what you’ve shown you will likely end up with a result that looks more like this:
A few things:
-Because you have a pipe, plus the outside lens, you will lose a lot of light in the gap. Most lightpipes rely on total internal reflection, to keep light bouncing around inside the material to improve the uniformity. You will lose that phenomenon and the outer lens would only be good for basic diffusion.
-Since the outer lens will just be a diffuser, try to minimize or keep any mounting features uniform. The different thicknesses you have in place for the snap features will cause different light and dark spots and make it harder to make uniform.
-You’re probably at a point where if you are close to being able to prototype this with some 3D printed parts, you would learn a lot through trial and error. You can mock this up with 2 of your chosen LED’s very quickly.
You may decide once seeing where the light falls on the outside, to further refine the shape based on the areas that are light or dark. Or for this use case, partial or less than uniform lighting might still be totally OK.