If getting rid of your fish is a viable option...yes.
Then before adding any back...get your live rock and everything in which you think may disturb the water chemistry finished before you get anymore.
Many LFS's will give you a credit or even buy the fish from you.
Take your time with all of this...time only helps the tank.
The CC, in my own personal experience...will trap debris and create a nitrate nightmare...I did it in my 90 and it was too hard to keep it vacumed as the tank is in my family room and the filtration is in the basement below..that is where I do everything, water changes etc...and the sand looks so much better then the CC. A word about sand...if you decide on and have available to you, the Southdown...ensure the bags are closed, not broken open or anything like that. I purchased my own sand from purearagonite.com...had to pay shipping but I got sand that wasnt sitting in the outdoor section with fertilizers, chemicals, and careless employees.
A refuge is not required...it is a very valuable addition and serves many purposes...I have two of my refuges setting next to the sumps...they are supplied directly from the return pumps and siphon overflow back into the sump. One is lit with a 75 watt grow light, and the other is lit with a 96watt pc, and two 40 watt tank lights. The 96 watt pc I just moved over it last night and it is a smartlight with one side actinic and the other i think is 10k. One refuge is a 5.5 gallon tank, and the other is a 7 gallon rubbermade clear store flat plastic under the bed storage box...works well, in it I have about 3 inches of sand and caulerpa, mangrove and a ton of pods. The 5.5 has some live rock, mangrove, caulerpa and pods.
The third refuge is just a "toy around" type of thing, above a ten gallon tank...just something i mess with and sometimes use as a QT. I keep a blue devil damsel in there...he has been in there for several months now and doesnt seem to care...his concern is eating...nothing more, nothing less.