Answer:
I already helped with 1, and i don't know the answer to some of them, but here are some more:
Number 3 is actually a common riddle that exchanges 3 different animals/foods throughout cultures. Here's the wikipedia page for "wolf, goat, cabbage" with the solution to the riddle.
https://en.wikipedia.org/wiki/Wolf,_goat_and_cabbage_problem
here's the solution with the animals from your version put in. It works because the crocodile doesn't want to eat the peanuts.
1. Take the dove over
2. Return
3. Take the crocodile or peanuts over
4. Return with the dove
5. Take the peanuts or crocodile over
6. Return
7. Take dove over
and for number 6, the answer is the letter U.
