I think he stated that the artist will hold onto it in the interim.
I think the below referenced part of the quote makes it clear that he was not leaving it with the artist, and rather he was taking it with him, to be "re-presented" to the artist at a later Con.
That would be correct. Can the book be given back to the original artist at a later date, to then be submitted to CGC for yellow? I have a hard time believing that it would make a huge difference, as long as the original artist presented it. But, there are rules for everything it appears
That is correct. Once it leaves the possession of the artist, it is no longer eligible.