From our experience with the game, here are some points that led at least to some ingame discussion how to
its supposed to work. I added our groups conclusion to each. Could anyone please clarify some of them?
They're not neccessarly vital to the game, yet I'd like to know if our judgement was good or not. 
Can the keeper cast a damaging spell on another investigator using the "Uncontrollable urges" card? - My
opinion yes, but group has doubts.
How do "outside" rooms work for fire and horror checks?
If horror checks work along the tile edges its kinda weird that there are situations where an investigator
is one space away from a monster and doesnt have to do a horror check, and if he moves onto the same tile as
the monster he has to, although he can be as far away from it as before, or maybe further. - We went to a
house rule where horror checks apply as long as there is LOS.
Is the keeper able to spread fire into gardens / outsides? -My opinion yes, group has doubts.
If the keepers plays the "take sample" card on an investigator, and the investigator, the monster and an
altar are in the same space, does the keeper immediatly get the 5 threat or does he have to wait to the next
round? - Group went with yes, but uncertain.
If the objective is revealed, do the investigators have to find all leftover clues to win? - Group went with
no. (this is a weird question, but someone asked it, so I put it here)
Does "escape from xyz" mean that the investigators have to spend a movement point to leave said room, or
just end the turn in that room? - Group went with spend movement point to leave space with door leading to
the outside.
Is the keeper able to play every keeper action card that doesnt state that its only avaiable once per turn
as ofter as he wishes and can afford it? - Group went with yes.
Does the latern only eliminate darkness for the investigator carrying it, for all investigators in his space
or even all in his room? - Group went with room, my personal opinion would be space at most.
Is every game ending that isnt described as a winning condition for either side a draw? Ie if the keeper
wins after the last event card is played, and the investigators win if they all escape, but one of the
investigators dies on their way out, but the others make it out before the last event card is played, is it
a draw? - Group went with yes.
Are investigators with the "kleptomania" trauma card able to steal starting equipment? - Group went with
yes.
Can an attrbute of an investigator be lower than 1 or higher than 10? Or in other words: When rolling for
attribute tests, does a 10 always mean a failure and a 1 always success, or is it possible that the
investigator may skip dice rolls completly, either because he's so boosted that his attribute is 11 or 12,
or he is so beaten up that its below 0 and therefor can resolve the pass / fail effects immeditely? - Group
went with at least 1 and maximum of 9 (ie 10 is always a failure), but uncertain.