The height to which a being is able to jump is not directly related to size. In fact, if air resistance is neglected, you could still jump to exactly the same height as you could when you were big. This idea was actually understood as early as by Galileo. Therefore, even though I’d be really small, I’d still be able to jump high enough to escape the blender – unless it’s a giant blender, in which case there’s probably plenty of clearance to lay under the spinning blades.

No, the answer is right. After the first person redistributes the coconuts, the total number of coconuts left is 6/7 of the original amount. After the second person the total is down to (6/7)*(6/7) = 6^2/72.

This continues until the 7th person, after which there are 6^7/77 of the original coconuts left buried in the original hole. This number has to be an integer, so the original number buried has to be divisible by 7^{7. The smallest such number is 7}7 itself. One coconut was thrown away, so there were originally 7^7 + 1 coconuts.