At a realistic standpoint I would have no idea on where to start on those traps. I also think the traps in STN should have a improvised and simple feel to them not extremely complicated, after all this is the apocalypse. Good ideas but I am going to have agree with @MrMoose , I just don't really see them fitting into the game. (although I feel like they would fit well in a game like "Folk Tale" XD) Good suggestion though.
1. A Candle left lit will have a life lighting expectancy of maybe 4-7 hours. depending on how big the candle is. the wax will melt and the flame will not be in the position of whatever flamable liquid uve mounted on this trap. You will also need to trigger for this flamable liquid to automatically spray when the trap is triggered. Dependant on Wind Condition the flame will go out on a candle which makes it 10x more less reliable. so no.. its not going to work.
2. making a bow and stressing the wood in a trap is broken idea. if u pull on a makeshift bow using a "bendy stick" with a string. the bow will after some time stay formed in that manner. so ur idea of using it in a trap is not going to work.