Why Garry?

Today, I pose a quick question to you all, and it surprises me a little that I never asked this question sooner.

Why, in Ib, does Garry also end up in the fabricated museum? My thoughts were always that Ib was picked out special by Mary, though I could not tell you why I believed such. It just seemed that such a lonely little girl would seek out another. Also, the fact that the messages to Ib in the museum are friendly and maybe a little playful in the beginning of the game always made me assume it was her (though, I suppose it is possible it was another painting, or even the dolls).

However, while Ib purposely ends up in the painting world, it seems obvious that Garry was not someone to be desired. There are messages strewn throughout the fabricated museum that talk about being away from adults, and Garry is certainly an adult (in comparison to the girls if nothing else). Mary, of course, also talks about how Garry is a "grown up" in a negative way. Though she may or may not have minded him being around in the beginning, it still seems that she wanted Ib to visit her most of all (because, once again, they are of the same age).

So why does Garry end up in a world where adults are unwanted? I have heard many fan theories that Garry is in some way related to Guertena, but I do not believe that for a few reasons including that Guertena is clearly long dead by the beginning of the game, Garry does not recognize his name, Garry does not say he is related (and if he were related to an artist, it seems likely he would know and be proud), and it just seems to coincidental. Though, if he were related, he would certainly be drawn into the painting world.

But if he is not, then why him? Why does Garry get summoned there, too? There was at least one more child in the museum, though she appeared to be much younger than Ib. Perhaps that is the reason why she did not get pulled into the fabricated world. On the other hand, was Garry really the next youngest person out of everyone in the museum? 

I have no ideas, theories, or any background information that might make the answer even somewhat clear. All I have is this question: Why Garry?

It just seems strange that out of a museum full of people, Garry was the other person to be dragged into the painting world. Some food for thought.

...Though, coming back to the question, there is this:

In Mary's room, you find a diary where she remarks about the above. Perhaps Garry was chosen because Mary only wanted to take his place, something she did not want to do to Ib, who she wanted to be friends/sisters with. Still, that does beg the question of why Garry? Why peg him as her victim when there were so many others?

The more I think on it, the more I wonder if it really was Mary who got Ib and Garry to come into the painting world. Perhaps it was one of the paintings or dolls, but that still does not make sense since none of the paintings wanted Mary to try and leave in the first place.