If you breed Eevee you can get Eevee eggs, but otherwise, no, you're only given one Eevee from Bebe in Hearthome.
no
Yes. You can use it as often as you like.
Yes, you can duplicate Pokemon on Emerald more than once.
I believe that Pokemon platinum is better than diamond and pearl because it offers more features, and allows you to do much more cheats and tricks and get more Pokemon through normal game play than Pokemon diamond and pearl. Yes, it is.
No they can't.
You will need a Pokemon GBA game and the national Pokedex in Platinum and have talked to Professer Oak in front of the Pal Park. You can't migrate more than once a day and you need a DS or a DS Lite. A DSi has no GBA dual slot.
nope
None!
Platinum has more Pokemon 247 than DP and DP has the same amount of Pokemon 151
No, even with the event.
as long as the event is still going on, there is a way. it involves getting the same "event gift" in Pokemon diamond/pearl and trading to Pokemon platinum.
yes Yes You Can Buy Them