You cannot get more than one starter in the game. The starter Pokemon are only given out once. To get another, you must trade for one. You can also breed your own with a Ditto for more of the same one.
Totodile, Chikorita, and Cyndaquil.
There joto staters
i am sure you can see them but not catch them
chikorita,cyndaquil, totodile
only with cheats or by trading
only if you trade from pearl/diamond/platinum
with an AR
toddile,chikorita and cyndaquil
By Ruby I'm assuming you mean the Hoenn starters, then yes, you can get one of three of them in HeartGold/SoulSilver
yes but only by trade
If you have a friend who owns Platinum, Diamond, or Pearl ask to trade with them.
One of the three Hoenn Starters. Treecko, Torchic, or Mudkip.