Treecko is the grass type,Torchic is the fire type and Mudkip is the water type. If you are choosing one I recommend Mudkip as it evolves into Marshtomp then Swampert which are both water ground types.
By Ruby I'm assuming you mean the Hoenn starters, then yes, you can get one of three of them in HeartGold/SoulSilver
It is impossible unless you hack
The starters in ruby (like sapphire) are: Torchic Mudkip & Treecko In ruby, instead of getting the legendary Kyogre, in the story line you'll find Groudon.
All The Shiney Pokemon You Can Get In Pokemon Ruby Are All The Pokemon You Can Get in Ruby Any Pokemon Can Be Shiney Even Starters and Legendaries. So There Are 200 Shiney Pokemon You Can Get In Pokemon Ruby.
one of the three johto starters: totadile, cintaquil or chikorita
I don't think so.
You cannot, you are only able to recieve one.
You need a game sharkYou need a game shark you can also get them from emerald but you have to complete the pokedex in emerald to get oe of the three starters from pro. berch
In Pokémon Ruby (and Sapphire/Emerald) the three starters are Treeko (Grass type), Torchic (Fire type) and Mudkip (Water type).
You can only receive the other starters from other ruby sapphire or emerald players you can't catch starter Pokemon ever.
It is Impossible to Clone on Pokemon Ruby. I for starters, have tried most ways of doing it, but saly enough, thee cloning rules only apply to emerald.
Obtain 200 Pokemon in Pokemon ruby, sapphire or emerald, then go to professor birch and you get to choose one of the johto starters, then you migrate the starter you chose to Pokemon, diamond, pearl, or platinum.