1. the stray animals that "feed" off the infinitely spawning "vermin" creatures always have a ridiculous population number, so it is normal in this game for some time now
2. full-game features will be added in the next 60 years unless dfhack steps in and makes it the next 10 years alteast in a band-aid solution, just sprint
3. answered
4. answered
5. wiki is usually years behind, sometimes you have to find out things yourself, the discoveries is packed with disappointment when you realize you have been doing something wrong the whole time
6. trading in general is only useful for getting gear; collect gems that are described as "large cut longmaterialname gems" or "cut geologicallyaccuratematerialname gem", then use it to trade with a dwarf civ or an advanced goblin civ if friendly for their steel weapons (and gear if your the size)
unless you head straight into a vault and find divine metal gear
7. any meat is edible unless it is from a sapient being such as a troll, procedural night creatures or other humanoid races such as goblins. edit: forgot to add in that heating meat up doesnt do jack, im also going to add that alcohol doesnt freeze in cold weathers
fun fact; if you encounter tombs with skeletons in them you can actually butcher them and use their produce. it also applies when your a necromancer and resurrect the listed beings; kill them afterwards and butcher them to use their produce for crafts(the meat otherwise will be useless as necromancers dont need to eat)
8. it doesnt matter which hand the weapon is in
9: W: means your primary weapon, if your using two weapons your going to get your head exploded by something's stone fist/paw or silver arrow/bolt because of lack of shield even if you have a helmet with padding, you cant parry unarmed attacks unless you catch their attacking move with the wrestling interface. A: means the primary armour your wearing that has the biggest coverage, usually mail shirts or breastplates appear as primary
source: i power play through adventure mode, could say i have interesting stories but im horrible at that(actual stories that atleast isnt just me one-shotting a megabeast with a copper utensil). anyone else may correct me on a thing or two or maybe have a better answer in general