Would this be appropriate for quail? How much protein do the pellets contain?

The pellets contain 16% protein, according to the nutrition information on their website. The pellets are too big for my medium-sized hens (Ameraucana, Welsummer), so they would not be a good choice for quail. Plus, quail need a lot more protein than chickens do. I don't think this pelleted feed is a good choice for quail.

Can this be fed to a flock with both hens and roosters? How high is the calcium?

Honestly, I would recommend giving everyone the grower feed, while providing calcium separately for the hens. Roosters can be seriously harmed by having too much calcium. We found that out when processing one of our roosters, who had eaten some of the oyster shell before realizing he didn't like it and shouldn't eat it. One of his kidneys was twice the size of the other, and was discolored.

Does (scratch and peck feeds organic layer pellets chicken feed with grub protein) have fishmeal or soy in it at all?

they have a list of ingredients on the package it doesn't list that Organic Wheat, Organic Barley, Organic Peas, Organic Flaxseed Meal, Ground Limestone, Organic Sunflower Oil, Black Soldier Fly Larvae Meal, Organic Dehydrated Kelp Meal, Essential Oils, Vitamins, and Minerals. Due to supply chain availability, formulations may change – please review the feedbag label for lot-specific formulations.