I'm mixed. I found the elf in the cage (or rather talked to him) very late in the game; I had visited teh cave first so when I found him i knew who he was. However, I found 3 or 4 ways out and none of them were terribly burdensome. In fact the most frustrating one was where I was suppose to meet a guy on the cliff; i went there and escape via that route (then went back to escape by boat because I was looking for some hidden thingy to free some stone thing) but that quest never closed because somehow I didn't find the guy i helped escape (the one who wants the teleport spell).
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Anyway I'm pretty dense but i didn't have to search external sources for a way out of fort joy. Having said that I have no clue how one would know to bless pigs but give blood to burning man (which are opposite solutions for two burning entities - but i'm sure there is a hidden logic somewhere).
You should find the corpse in the slaughtering grounds where they create the meat golems. At least if you weren't there before helping him escape, not sure if he would still appear there otherwise. But even finding the corpse does not seem to complete the quest.
Blessing the pigs seems to pretty easy, I tried blessing the burning man, but that didn't help. So that is less obvious in my opinions as well. Thought both fires need the same solution.
