sun corals don't depend on light for food, so should be ok. But must be prepared to feed them regularly.
mandarins need a good supply of pods, so cannot put in fishes that compete with them for this food (ie wrasses). make sure tank is mature enough (websites recommend at least 1 year) so that there are enough pods. Best is have a refugium connected to tank so pods have safe place to breed.
alternately you can also go looking around for mandarins that are trained to eat prepared foods.
Easier gobies would be the watchman gobies, firefish.