In black and white you need I think shiny riku ,enti, or the other in the lost forest.
2
More than 495, 493 currently catchable in games. The other two are 5th Gen, Zorua and Zoroark.
In the title it says 'Gotta Catch 'em All'. Fairly self-explanatory.
You cannot catch a Totodile in FireRed. However, if you catch so many Pokémon Professor Oak will you give you one.
there are three that you can CATCH in pokemon emerald its Groudon, Kyogre, and rayquaza regice registeal regirock litos lotias
2
there are two they are called zorua and its evolution zoroark
you can catch as many legendary Pokemon but only once unless you have it on the computer
More than 495, 493 currently catchable in games. The other two are 5th Gen, Zorua and Zoroark.
about 470-480 In diamond pearl and platinum there were 493 total.
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.
I don't now but I believe that you can catch as many as you want when you encounter them.
Start by getting a lot of pokemon balls and then catch as many Pokemon as you can. Just catch Pokemon till you get to 200.
425
you don't need to catch them just see all the Pokemon in the hoenn pokedex
Excluding events, 150. This counts Zorua/Zoroark as events. Including events, 156.
You can catch as much as you want.