There may be an action replay code, but I'm not sure. And, you can always trade from another game. Oh, and if they don't want to loose their totodile, put it and a ditto in daycare, and when you get an egg, hatch it. And it should be a totodile, and you can trade that one. Problem solved!
It is in the beginning of the game when you are entered in Prof. Elm's Lab. If you chose Totodile your rival chooses Chikorita, but if you chose Cyndaquil your rival will choose Totodile. Other wise it'll be harder to find without those requirements, besides trading.
In the Hoenn Region, not only in Sapphire, you get those three Johto starters by getting a Hoenn Pokedex of 202. When you do, Professor Birch will call you with a Pokenav and you can choose either Cyndaquil (who I chose), Chikorita, or Totodile.
Unfortunately, you can't catch a Chikorita in the wild. You'll only be able to find it if you choose it as your Starter Pokemon or you chose a Totodile as your Starter (in which your rival will choose the Chikorita). Or you can trade another Pokemon for it in the GTS.
Chikorita Cyndaquil Totodile I recommend Totodile. Just for heaven's sake don't choose Chikorita. Cyndaquil's alright if you don't fancy Totodile. CHOOSE TOTODILE!!!
If you chose a Chikorita, your enemy will have a Cyndiquil. If you chose a Totodile, the only way to see it is to trade for it. If you chose a Cyndiquil, you will have already seen it. The easiest way is to trade for it.
Totodile, Chikorita, and Cyndaquil.
Your rival will have Chikorita if you pick Totodile as your starter pokemon.
your rival should have chosen cyndaquli if you pick a totodile No if you chose totodile he chooses chikorita but i do not know i am sorry you could go to seribii.net and go to the the pekearth and click on the routes and the see which trainer has the Pokemon yo choose lot of work but you can eventually find it. http://serebii.net/pokearth/index.shtml
Cyndaquil, Totodile, and Chikorita.
Totodile, Cyndaquil, Chikorita
cindaquil, chikorita and totodile
Cyndaquil, Chikorita, Totodile