You find Sneasle in the Ice Zone after starting to decorate the ice tree for Kirlia. (Talk to Kirlia, then to Delibird. He will give you presents for becoming certain pokemons friends.) hope this helps!
To get Sneasel in Emerald you must trade him from FireRed or LeafGreen.
actually you don't find a sneasel in Pokemon sapphire you only get it by trading
You can get a Swellow by catching a Tailow and make it evolve into a Swellow.
Or catch it on the route 115 by Surfing to a small place.
Once you put two items on the Ice Tree, he will appear near the intersection.
Not there
Play park
set a record
He is in the beach zone
bayleaf is not on pokepark wii only chikorita is
Talk to everyone
I guess you have talk to sneasel and he will ask you to play chase with him/her, press the yes button and if you beat it at chase it will be your friend (sneasel is quite fast).
In the Train Depot in the second game
Around the Drilling Machine where Hitmontop is
Can't find either maybe not a Pokemon in this game
hit the tree outside the haunted house
No, you can't see mewtwo in pokepark wii