It isn't a coincidence. Shaymin had a good reason for giving this gift to Fighters, other than the fact that all three trainers had Fighters that were special to them for some reason. (Blaziken is the son of the Ninetales that was Ishmael's starter, Breloom is a Pokemon that Shadow has wanted for years... But there is a bigger reason.)
And it does indeed seem that Jessica has become somewhat mad with power, recently. The cause of this is more than simply ego, as you'll find out soon.
By the way, I just got Pokemon Platinum. It seems that the character whom I called Pluto is referred to a "Charon" in the American version, most likely to avoid copyright violations. (Although I do not think that Disney owns the rights to that name, which was used for long before they were using it.) I'll continue to use the name Pluto when referring to the character, however. If I have to reference any other character that appears in the game, I'll use the American name. (I might reference Looker eventually - he's an interesting character, if only to let us know that Officer Jenny isn't the only cop in the world of Pokemon.)