About Peggy: It's either Peggy is the old geezer who took care of Jairo when he was sick, or Meleoron lied about him being his foster father.
http://www.mangareader.net/207-14251-12/hunter-x-hunter/chapter-242.html
http://www.mangareader.net/207-14251-13/hunter-x-hunter/chapter-242.html
http://hunterxhunter.wikia.com/wiki/Peggy
If Peggy is Meleoron's foster father, and if Peggy is the old geezer that lived next door that took care of Jairo when he was a kid, it would make sense. Jairo did owe the old geezer a great deal when Jairo was sick. However, one would have to assume that the old geezer lived through the 9 years that took Jairo to found NGL and the years NGL has been in existence until they were devoured by vermin, err, Chimera Ants and reborn. If the old geezer did live through those years, the closeness Jairo and Peggy might have had should be self-explanatory in most cases, but I will still explain it. Jairo could have just repaid the kindness and concern of the old geezer by sticking with him throughout the tough times, and in turn, made the old geezer proud and fatherly enough to Jairo to want to carry around the NGL manual all the time, which is Jairo's creation. Also, this would reinforce the reason for Meleoron's actions, which is, as he claims, to avenge his father.
If what Meleoron said about Peggy being his foster father is a lie, it would still make sense, in the context of using this emotional reason to make an ally out of Gon, which would aly him with the Hunters. He must have found Gon was with the Hunters while spying on him, which he could do when he was offscreen after him and the other Division Commanders dispersed from the old colony after the Queen died. He might have also been spying on Gon and the Hunters earlier.
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About the clothes: Jairo wore a heavier hooded... jacket (lol I ran out of English) than Meleoron. All while strolling in a hot-looking place crowded with people. Why Jairo would wear that would make sense if he's Meleoron in that it does the following:
1. The hood cover's the face in a way Meleoron's hood didn't.
http://www.mangareader.net/207-14198-8/hunter-x-hunter/chapter-189.html
http://www.mangareader.net/207-14213-9/hunter-x-hunter/chapter-204.html
2. Meleoron wouldn't have to use Zetsu, In, his nameless first Invisibility ability (which would most like still use Nen, and gives off things like smell anyways, which would make him suspect to things like Hunters and chimera Ants alike; also the invisibility can be overridden by En), and Perfect Plan (which is dumb, since that means he will have to hold his breath) to hide amongst people. If Jairo wanted to use Zetsu he wouldn't have to use the heavy clothing then.
3. The heavy clothing effectively hides Meleoron's tail, which the clothing he normally uses doesn't do at all.
http://www.mangareader.net/207-14213-8/hunter-x-hunter/chapter-204.html
4. The shoes hide Meleoron's feet, and Meleoron's feet are small enough to wear normal human shoes.
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There's no mention about Jairo leaving the nest ever since he was born, what was said in the manga was that Jairo left the Queen's control and had enough will and determination to resist the Queen's orders. He could still be Meleoron if this is the case. He could just hang around, acting like he's Ant-minded, just to cover up the fact that he still has his pride. All while planning for the best set of moves.
http://www.mangareader.net/207-14212-15/hunter-x-hunter/chapter-203.html
http://www.mangareader.net/207-14213-9/hunter-x-hunter/chapter-204.html
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Here is a small comparison of Chimera Ants that wanted to move against the King in some way.
1. Leol: Tried to make his way up using favors, waiting for the day the King might owe him one, so that he could have his ability. Did not ally himself with humans.
2. Ikarugo: Defected from the King's side after finding a friend in Killua.
3. Werefin: Wanted to become a "Shadow King". Became an unwilling accomplice by the Hunters after giving up against Ikarugo. Did not seek help from humans
4. Other Division Commanders like the crocodile, Zazan and Zitoh: wanted to become Kings in their own way, that doesn't necessarily pit them against the King. Did not seek help from humans.
4. Meleoron: Actively spied on Gon, and approached him to be his ally in his vengeance against the King. Sought help from humans, especially from a Hunter. This would effectively make him an ally of other Hunters, who are the ones who have the capability of actually defeating the King.
Meleoron's approach would fit with Jairo's mindset which is logical and constructive.
http://www.mangareader.net/207-14213-9/hunter-x-hunter/chapter-204.html
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The ability to make friends: Jairo had a friend in Werefin's former life, and the latter remember the former fondly.
http://www.mangareader.net/207-47012...apter-296.html
http://www.mangareader.net/207-47012...apter-296.html
Meleoron hit it off with Knuckle. If Jairo and Meleoron are the same, although they might be planning some evil things, it just shows that they could still be charismatic (so Meleoron could be Specialization?)
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I have already said something about the name controversy and the traits of Jairo linking to Meleoron's abilities.
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Now, I don't know if these are all of the ideas I posted about Jairo being Meleoron, because I didn't read through all my related posts yet. But hopefully this covers most of the points. I would do a review of my posts again to see if there are some points I missed.