Myself, as well as many other, have used Krylon Fusion to paint things that are now in our aquariums. It sounds like Marine Paint is another option.
As for the engineers response, why would Marine Paint not leech chemicals back into the water? Everything leaches chemicals, especially plastics and rubbers. So that would include, skimmers, PVC plumbing, powerheads, power cords, eggcrate, etc . . .
Personally, I wouldn't paint a dead sea fan and put it into my tank, especially if you have living corals, but to each his own. Good luck, Luis.