Okay.. Well. In that case, I don't own the species so most of my knowledge actually comes from this forum. But to give you a quick summary:
Yes, they might fly up and kill themselves. Not necessarily as a response to noise though. I have button quail, who don't give a **** when my father uses an extremely noisy circular saw in the room next to them, and in general coturnix are supposed to be calmer than buttons. But I did send my buttons flying once, by picking up a plastic bag from the floor next to the aviary. I suppose the combination of the sound and the sudden appearance of the large unknown object caused the reaction. To avoid deaths due to boinking, you can either place them in very low cages - >1 foot, I think - or in aviaries, where they will probably loose speed before they reach the roof. Or you can pad the roof with something soft or make it out of plastic garden net or similar - just make sure the cage is predator-safe.
Yes, you can raise them near chickens, but chickens carry diseases that quail have little resistance against, so it's not advisable to do so.
Under some circumstances, coturnix quail may go broody. Usually in relatively large cages or aviaries where they have just a few cage mates. But it's not a regular occurrence.
Yes, the males will very likely fight if you place more than one in a cage.
3-7 females for each male.
I have seen pics of slanted cages in this forum, so I assume it's a good idea.
Ground pen = increased risk of worms and coccidiosis, wire bottom = increased risk of bumble foot and leg issues, in particular in very heavy birds.