The only Pokemon that can be transferred is manaphy.
Sadly you can't as you can catch rare Pokemon fairly easily on Pokemon ranger and it would be cheating especially with those rare legendaries. Although you can trade heartgold, soulsilver, pearl, and diamond with platinum. You can also trade Pokemon from earlier generation games using your internet.
No, but you can transfer from platinum to black or white using poketransfer of relocater.
No (unless you trade through platinum first)
No but you can use the GTC on wi-fi to trade
you can using cheats,trade or using pal park but without 1 of those 3 u cant
Sadly it can only be found using Trade or migration
You can do a local trade just by going to the top floor of any Pokemon Center and using their services.
to get the old Pokemon into Platinum you trade them in from old games after you get the National Pokedex using the Dual Slot in the DS you put a gameboy game in and trade 6 Pokemon per game per day.
Trade with a friend or through global terminals trade using wi-fi connection
You have to have Pokemon ranger and beat the game. Then you unlock ranger net and enter a code with the buttons and you will get a special mission. Complete it and you will be able to transfer the Manaphy egg from Pokemon rander to dimond or pearl.
you will get it by using zebstrika to trade a lampent with a girl in flamerny city,after you trade it will evolve to chandelure
you trade using the global trading station (GTS) or trade with someone that you know that has one