Next Vessel (Spoilers)

One thing I didn't get, although possibly it was never explained so we can only speculate, is how the next vessel is chosen. Is the next vessel Malkovich's own daughter? If so, does that mean that the previous vessel (Lester) was Malkovich's father?

Is Lester somehow able to control who the next vessel is, or at least figure it out somehow?

Also, while we're on the topic of Lester, he initially appears quite a simpleton but then later seems to be cleverer in what he does - might be be pretending to be a simpleton in the early office scenes?

Are there any clues to how Lester found the portal, or figured out his 44th birthday theory, or selected or found hosts, or is none of that explained.