Reef tank w/ no clearance below for sump

I have a 65g Oceanic tank built beneath a 42" tall bar. Beside the tank is a cabinet with a 10g sump that houses my Reef Octopus 150sss skimmer and some chaeto with a grow light. Water gets to the sump from the display tank by way of a canister filter that draws it out and dumps it in the sump. The sump has a 1-1/2" bulkhead in the side of it that let's the water gravity feed back to the display tank. The display tank contains about 100lbs of live rock and 80lbs of Carib Sea live sand. I've had this setup for about six weeks with basically no bio load, a single dottyback and a couple of camelback shrimp. I recently visited a local aquarium store as I was interested in adding some fish or coral per the owner's advice. He said if I wanted to do a reef tank I should start with coral and add fish later. He said it greatly complicates things when starting with fish. I've had several freshwater tanks over the years but this is my first venture into saltwater so if what he is saying is true I'm fine with that. When I explained my equipment configuration he advised me to do a fish-only tank due to the canister filter. This was a little disappointing as I'd really had myself psyched to do a reef. I have a limited space cabinet next to the tank for equipment (37" tall, 13-3/4" wide, 21" deep). My question is, is there a way I can get my setup reef ready with the given space and configuration? Would removing some portion of the canister stack(bio, mechanical, etc) and just using the canister for it's pump be sufficient? I don't want to set myself up for a maintenance nightmare.