Where is Home? and the underwater island by imthinking

Apologies to anyone who may have brought this up. There have been massive amounts of theories coming in daily it seems and I don't have the time to read through all.

MiB has said he wants to go "home" and that he is trapped. A couple of my friends thought that this "home" he is trying to get to is the temple. At first I thought that it was just somewhere off the island. But after thinking about it for a bit, a very simple idea kinda slapped me in the face. Mib's "home" is whatever time period he was living in before he became the smoke and where he could still feel all human emotions as explained last episode.

I wouldn't be surprised if he used to have a family. A wife and children. Why would he be interested in going to the temple? And he has been on the island for hundreds of years, so why would he want to leave in the present time? There would be nothing for him. So here's what I propose:

Mib knows the island well. He knows what he must do to get back to his time. This may be why he is recruiting. I think that he is going to somehow time travel back to his time, but in a different way than we've seen. Whether it's using the donkey wheel in a different way or by using some other device we haven't seen. His time traveling back to his original time is going to cause the island to sink and is also going to be the event that causes the "sideways" time line.

I know there are some holes but let me know what you think. I would love to be able to expand this with your help.