Mareks induced paralysis is transient so in the unlikely event a bird recovers from the virus, they can recover use of their legs. It's not common but possible, it depends how much the nerve sheath has been permanently damaged. It could be that your birds with the odd presentation of the disease were/are beginning to recover from the virus but actually succumbed to lymphoma caused by the virus? I'm only throwing ideas around. I don't know for certain.
It sounds like JoJo may have caught Mareks earlier than you thought or he had some sort of pre-existing Neuro condition or injury that affected how he walked.
Even if Nohope doesn't make it (I'm crossing everything that he does, he's a superstar and a real fighter

), you're giving him the best life possible. And as long as he's still enjoying his French fries, snuggles and is free from pain, all to the good. You are caring for him beautifully.
Have you thought about supplementing his diet with gamma linolenic acid(GLA)? It has been shown to be beneficial in reducing inflammation of and protecting the nerve sheath. Hemp seed, blackcurrant seeds/oil, safflower and borage are all rich in GLA and safe for chickens.
Charcoal is a great shout but unfortunately, it won't detoxify heavy metal poisoning. You need a specific chelate for that. Vitamin K is also useful to have on hand for chemical poisonings, e.g. rat poison.
Don't give up. You're a great chicken mom