I don't see anything obviously wrong with your design, but I do have a couple questions.
I assume you will, but to be clear, you will have a split drain with a slower-flow going to the fuge?
What do you intend to use the primary refugium compartment for and why do you have a separate compartment for your chaeto?
Do you believe the first bubble trap is necessary given your use of 3 baffles? Won't the skimmer render the first trap moot?
If you intend or later decide to use a micron sock on the primary drain, how accessible will it be? Will you hate messing with it? (I wish I had asked myself this one.)
Have you decided if you are going to run carbon or GFO? If so, then by what means?
Genuine question, no judgement... why have you decided to split your sump length-wise? How accessible does your refugium need to be?
How much gph will be going thru those baffles? That will decided how far apart you need to place them for maximum effect.
Is you return pump inline or drop-in?