OK something about this drawing I really like...
now on the the reefing stuff. looks like you plan to use a HOB overflow from the fuge to the sump? big point of failure. if you must use a HOB get the one from life reef only one I would ever trust.
but why not make it simple drill the tank and use an overflow back in the the sump?
have you thought of an ATS could sit on your 55 gal sump.
BTW I think a 40br is a better size for the sump you will thank me later

or the new 60br they just came out with.
i believe per sq inch of space ATS do a better job. IDK just a thought.