two questions 1: is it possible to get a level one pokemon and if not how come there are so many level 1 pokemon on POKEMON GTS.
If you see a pokemon on the GTS that is level one, chances are, it is hacked.
Here is how it goes..
baby pokemon (like pichu, elekid, happiny) are usually real pokemon, that have been hatched form an egg, and gotten at level one. (When you hatch a pokemon, it is level 1)
if it is an evolved pokemon, (Like raichu, clefable or wevile) it is hacked, since those pokemon cant be gotten without either leveling up 1 level to evolve, or needing a stone, but even then, the pokemon preceding it can not be found at level one, (Like pikachu) so it must be hacked.
Any legionaries lower than there original levels are hacked, without a doubt.
(Other than Manaphy, or Phione, since those are the only pokemon that can be hatched from eggs... that are also legendary.)
If a person puts a pokemon into the GTS and asks for a level 1 pokemon, of a pokemon that cant possibly be level one, it is for taunting / storage purposes only, ignore them.
Example: If a person puts a level 100 Blastiose into the GTS, and asks for a level 1 Mew, you can assume that the Blastoise is there for storage purposes only.
also, if someone posts an Arceus, chances are, it is either hacked, or it was gotten through a hacked event, the pokemon is real for sure, but the event used to get it, was hacked.
I hope this solves some of your issues.