For #4 we liked the symbolism of the icon, though we are trying to get away from the inverted tear drop shape since other possible competitors use it.
For #7 one of our team liked the idea of splitting under/ground as you did. Some also liked the compass idea, though there was some concern about a compass representing old technology. If there was a way to modernize the compass to make it more high tech, that would be helpful.
Orange, it turns out, was not popular with our group.