[cheeks69]

Jager 200W 15" Heater (I do live on SW Florida, will I really need a heater?)

Jager is a good choice and I would recommend a heater since there can be temp fluctuations which isn't a good thing for your fishes immune system.

Crushed white coral sand

I prefer aragonite sand but crushed coral will be fine. My suggestion would be to just put a fine layer and syphon weekly to remove any detritus buildup.

Artificial corals

I would also suggest you use Live Rock instead not only does it provide natural cover and food for your fish but it's an excellent biological filter.

Also for the first few weeks I was thinking of putting some Demsils in there.

Damsels are very aggressive and would possibly kill new additions especially if their small passive fish. Also using fish to cycle a tank is cruel and unnecessary in my opinion. Using uncured live rock or simply adding a raw shrimp can easily start the cycle or even adding some fish food would do the trick.