You just have to be very lucky (the chances of running into a shiny wild Pokemon just by walking through grass is 1/8600000), or buy Action Replay and hack your game to get one.
No, you cannot catch a mew in Pokemon Platinum without cheating.
you cannot catch a Pokemon without a ball...however you can get Pokemon through trades or from another trainer in the game
You catch and evolve all of the Pokemon you catch :P
no
A fleeing legendary pokemon
Use the Master Ball if you need to catch a Pokemon without fail. I'd suggest using it on a legendary, though - don't waste it on a common Pokemon.
Level 100 Pokemon do not naturally appear in the wild in Pokemon, so you cannot catch them without cheating.
No not every pokemon. You can't catch the starter Pokemon and many of the rare pokemon, you have to trade with Diamond. sorry ...
in pokemon emerald
you cant
Not without hacking.
You must first catch a Pokemon with pkrs which is extremely rare. If you want more Pokemon to catch it in the PC put the Pokemon with pkrs next to other Pokemon and they will catch it. Unfortunately it is complete luck if you catch a Pokemon with pkrs and there is no way of making one catch it exept for what i have put above. Hope i helped!