It's strange to me that Jacob's Brother walked every inch of the island as wasn't able to find the Light. He only saw it again after Jacob lead him to it.
I would say it's a good bet that the temple is at the site of the Light, and the stream is bubbling up from that. ?
The orchid would be where Mother and MIB were at the donkey wheel. It's possible that the Swan hatch is built upon another one of these wells, perhaps a place where they dug deep enough for the energy to have an impact which would explain all that craz-ay magnetic stuff when the hatch numbers weren't entered.
LOCKE: Oh, they weren't looking for water. They were looking for answers. A long time ago places like the one we're standing at right now made compass needles spin. And the people holding the compasses needed to know why, so they dug.
DESMOND: Did they find what they were looking for?
LOCKE: No, they didn't. The reason I wanted you to see this, Desmond, is because Charles Widmore is not interested in answers, he's only interested in power. And he brought you back to the Island so that you could help him find what he's looking for. After all, this isn't the only well.