Staggered hatches are definitely a challenge. In my experience, if the humidity is too high too early, you end up with more curled toes and hatch issues. If you can get a second incubator, that would be your best option, but if you can't, the higher humidity will be your next best option. The...
Quail will never be super tame unless you handle them for hours every day, but how calm they are depends on a lot of factors including their breeding. If you don't want to worry about culling extra males, you might see if you can find adults on your local craigslist.
Myshire is always on my goto list. I've heard a lot of good about Thieving Otter a well. They got their stock from Southwest Gamebirds and have developed several of their own special colours as well.
If you garden, raised garden beds make good places for pens. I keep mine on my raised garden beds after I harvest and move them around. They fertilize the beds and eat the bugs. The cycle goes kind of like this:
1 - plant
2 - harvest
3 - put quail on
4 - move quail
5 - water and let compost
6...
You should be able to recover them. If you go into your files you should be able to see the contents of your "trash" which will contain your deleted items.
On my phone (android) you go to Tools\storage\trash
Without a biopsy it's impossible to tell if a tumor is malignant or not. I would let the bird live its life as long as its eating, drinking, and pooping normally. If the quality of life begins to drop you may consider culling, but until then, I would just observe and let it be.
It might be a cyst from getting pecked, it might be a tumor. It looks clean, so I'm guessing that you've been making sure that it stays clean, which is a good first step. I'm not sure what else you can do unless a vet is an option.
I have to agree with @Susan Skylark. If that is prolapse that has been out long enough to dry up like that, it could be serious, but again, the first thing to do is that epsom salt bath. Make sure to keep them warm so they don't get chilled after their soak.
Check out the articles in the learning center on quail. There is one on incubation that tells a bit about the different types of incubator.
https://www.backyardchickens.com/articles/category/quail.32/