this is just my opinion but i dont think your tank was mature enough to make the fish feel comfortable is my theory, from what i read you started with all dry rock(100%) only 1 month ago ??
in order for fish to feel comfortable and not stressed their surroundings have to be what they usually are use to.
so with dry rock not even one month old chances are you dont have a large supply of vegetation and natural food?? theres pprob not an abundance of clean up crews like stars or pods.
nitrifying bacteria is one thing but in order to complete the loop and make it workable there needs to be some life present.
i had this talk a while ago with someone about a 6line wrasse, for example your usual wrasse hunts all day , while it may take prepared foods it still hunts.
when it cant find food or even see food available it creates a panic(fish dont know what we know) as they freak out and look harder for food and none is there they start to stress.
i dont believe in that if you feed a fish lots he will fight ick i believe that food heps but doesnt guarantee it , the more a fish stresses the worse it gets.
i would do the same as you now and wait it out , i wouldnt even necessarily wait for a fallow period i would look more into adding things to make it more of a full enviroment.
i took some fish the other night off a friend there were 4 of them , they were covered in ick , the next day after being in my growtank not a spot on any of them i didnt even have a chance to feed them , in fact my tank is now over populated as i added 14 fish last week from someone elses set up so were talking almost 20 fish in a 50g tank in a span of one-two weeks while some were badly sick.
all the fish are fine now with no ich visible , the only thing i figure like i have for years is besides food you need to give them the full enviromnt they are used to in nature.
im not saying its not possible that you could have introduced marine velvet only you would know that but im saying that maybe theres a small underlying issue that is working against you.
good luck buddy im sure youll pull through this it happens to us all and once your over this small hump things have to get better right?
cheers