Well first off, THANK YOU for rescuing them and getting them OUT OF THERE!! You are an angel.
I'm sending you a big hug.
I was speechless when I read your post about how they were living. That "black stuff" could be a few things. Someone just posted about maggots on their turkey. Please read this thread.
https://www.backyardchickens.com/forum/viewtopic.php?id=536196&p=1
Do your turkeys have signs and symptoms of respiratory problems? When my Tom turkey first had his respiratory problem, I noticed that he had a few black scabs but not as many as your tom has. After administering the meds (Tylan 50), the scabs fell off, went away and never to be seen again.
If it were me, I would, of course, quarantine them WAY AWAY from your other animals. I would go as far as giving them a GOOD GOOD GOOD bath. Do you see any signs of lice or mites? I would also dust them with Sevin Dust to get all of those nasty bugs off of them.
I don't know if the scabs are from Fowl Pox or not. You could also put Iodine on the scabs as well.
Your poor Tom looks so sad. I feel sorry that they had to live like they did. But now they have a good home.
Can't wait to hear back from you about your turkeys.