X2. For right now, I would stop adding chicks until things calm down. Whatever you add later should be vaccinated day 1 and quarantined for at least 2 weeks, the longer the better.I too had the first necropsy come back inconclusive and it was extremely frustrating. My birds kept dying or having to be culled, but no official reasons. The second one done, proved the Marek's.
One thing, if you suspect Marek's and I think you have good reason to, please act as if it is a proven fact. You need to look at this as if 'you' have Marek's, not just your birds. You can carry it with you to feed stores, neighbors' chickens, etc.. You really can't be selling or giving away any of your birds any more either. To do so would be unconscionable. All it does is spread the disease to others and possibly wipe out their flocks. It also gives the disease a chance to mutate to a point, that any of the vaccines available right now, could become totally useless against it. This is some serious doo doo here and you need to be as educated about Marek's as you can be and aware that there are others out there with it in their birds, with no idea what it is, or don't care. Please don't become one of them.
Okay...off my soapbox now. I am hopeful you will hear back today and be able to get the local help you need to find your way. To have someone who is that close and able to do a visual of your birds would be great.
Don't feel guilty. Most people do add chickens all the time to their flock. Eventually you'll add someone with Marek's.
Now I go to swaps and look and hang out, and if I see a breed I like, I get eggs and hatch and quarantine them.Or I buy vaccinated chicks from a hatchery.
It seems that Haunted has developed some pretty good ways to deal with Marek's mentally and physically. You're not alone.