Go to Route 210 and use the Pokeradar, he's fairly rare but you'll eventually find him.
you need to have a pokeradar on route 210 which you get when you beat the elite 4
Yes, you can breed Kecleon in Pokémon Ruby, Sapphire, FireRed, LeafGreen, Emerald, Diamond, Pearl and Platinum.
No, kecleon appears in the grass normally like any other wild pokemon. But you have to use the Pokeradar, and it's kind of rare. It appears on Route 210 (North).
you have to find a dungeon kecleon shop
You can find Kecleon in any dungeon in Pokémon Mystery Dungeon: Blue Rescue Team as long as you can find one of its Kecleon Shops in the dungeon however you will need to steal one of the items in the shop in order to get them to attack them and in order for you to have a chance to recruit them.
You can find them in the Kecleon Stores in dungeons.
So far Kecleon does not have an evolution.
the Pokemon you can find in diamond but no pearl are: Seel Dewgong Mr. Mime Scyther Murkrow Larvitar Mightyena Silcoon Aron Kecleon Cranidos Stunky Stunktank Dialga
Transfer from Pokéwalker. Route: Treehouse (15000 watts, after receiving national dex) Kecleon Lv 30 5000+ steps Rare Feint Psybeam Shadow Sneak Slash
actually you can get it using an ar but it is not a shiny. the shiny kecleon has a blue stripe instead of a red stripe, but is still basically green. i don't know why the purple can be gotten in diamond with the ar, but it is possible. there is somthing you can't do with it but i can't remember what.
Kecleon doesn't evolve
Kecleon is a normal type