When I started my first fortress, I planned to try everything DF fortress mode can offer. While I already tried most things, I didn't plan to finish the game soon. But, suddenly, my military dwarves started killing each other, in fits of chaos. Usually, 4-5 dwarves get killed, before it ends, and starts again, 20-30 minutes later. I have already lost more dwarves to chaos than to enemy sieges or "accidents". So, before my fortress gets depopulated, and my military gets degraded from a mighty "we take zero casualties while fighting titans and 70+ goblin&troll invasions" dwarven legion to "let's send some untrained civilians, who didn't even have time to equip armour and weaponry" rubble, I want to try everything that I didn't do yet. While I don't have problems with the zoo, mechanisms and traps, and training beasts, I have problem with some other things.
1. Textile&leather&paper industries. For some reason, my dwarves refuse to make any leather stuff, despite me producing the said leather. At the same time, the dwarves butcher&use leather for their own needs, and I'm able to butcher animals too- but I get no tanning options and no "use the leather" options active. Without leather bags,I'm unable to make paper from plants. Without leather, I'm unable to make parchment, so, my paper industry doesn't work too. Without leather, I can't produce quivers (well, I only managed to produce 3-4 in a fit of luck) and waterskins. The same problem goes with my textile industry. For some reason, while the dwarves do produce some stuff, I'm unable to produce it myself.
2. Missions. Do the dwarves require leather waterskins to stay hydrated? Or can I send them without having a running leather industry?
3. Caverns. If I pierce a cavern layer, will I get instantly attacked, or not? Does the attack pause the game, like the attack of the surface titans? Should I have a squad of military dwarves ready in the mines, or are the cavern beasts the same as the surface ones, not invading my fortress, and only attacking those dwarves that are neareby?
4. Steel industry. Can the flux needed for steel production be found in the cavern layers?