1. I'd expect bark regrowth to be slow, but I don't have any real life knowledge.
2. Meat sacrifice goes towards the spirit of the forest, fish to the one of the water. It should be possible to sacrifice to both in the same day (for a while it was one or the other).
3. Given that smoking is done in a sauna, I'd expect tents to be too draughty. Note that a player made "sauna" works for smoking, but not for the quest requiring a sauna stove (as players can only build regular stoves). Thus, I'd expect the inner dimensions to be 2*1 (my saunas are always 3*1), with one of those tiles taken up by the stove.