Regarding the feature of throwing-out:
Yes, indeed, you get thrown outside if you sleep in a house/keep without permission. Sometimes even if you sleep with permission. Practical joke, most probably, or just the house/keep owner being an asshole. Also, 'Stunned' probably simulates waking up and being unconscious is DF's way of saying 'asleep'. Can't explain the missing kidney though, maybe bogeymen came by while you slept.
Regarding the dragonfire:
If you can, fight it on the (dry) grass. Block the dragonfire and let it ignite the grass under the dragon. It will burn up in its own flames. If you can't, well, a shield is a must, or ten shields if you can get them.
Regarding the elves:
Some people come to DF with the assumption that the local elves are the tolkienesque mystical beautiful kind noble people, just like in the vast majority of works. Some people come to DF after feeding on things like Boatmurdered and various player tales, hating elves for the sometimes-'imposed' 100 trees limit and a phobia of all things wooden and made from animals, or for being portrayed as 'the better people' in other works.
But DF elves are a peculiar case. They're way different from the usual picture and the dwarf side has a point here - they're cannibalistic, militaristic, sometimes quick to anger and send ambushes and sieges that are only of low danger because they use wooden equipment; they've been known to dominate entire worlds in a couple of centuries if their wooden equipment restriction was modded out. However, they can be genuinely helpful at times - their caravan is yet another potentially-life saving chance bringing what your fort lacks or needs the most like the other caravans, and they now bring both cloth and animals regardless of how much they like you, and they bring a lot of wood, which kinda suggests hypocrisy on their part regarding their ultra-greenness, but can potentially keep a fort afloat in the bed and coal department and provide the much-needed resources in treeless areas. All in all they're pretty grey, just like every DF race.