Fraxinus

Hey, I saw your thread got locked and wondered if you still need any help?

Thread was locked so I answer by VM.

The order doesn't matter. However, to trade between FRLG and RSE, you need to obtain the "Ruby" and "Sapphire" items in FRLG, and you also need the National Dex in Emerald.

You need two GBAs and a Link Cable (or Wireless Adapter) to trade between 3rd gen games. Wireless Adapter can't be used with Ruby or Sapphire. Unfortunately there was no Wi-Fi back then. :( GBAs should be cheap now, though. You can get even a second-hand DS for a fair price.

Emerald is the third version that complements Ruby and Sapphire. Differences between Emerald and the other games can be found here: http://bulbapedia.bulbagarden.net/wiki/Pokemon_Emerald. I personally think you won't miss the Pokémon that aren't in Emerald, though. Meditite/Medicham, maybe Zangoose are good Pokémon, but they aren't must haves. Differences between Emerald and RS aren't as big as the differences between Platinum and DP, however I still recommend getting Emerald over RS, because of the Battle Frontier, improved Safari Zone, and possibility to get both Groudon and Kyogre, as well as a Johto starter (Chikorita, Cyndaquil or Totodile).

Emerald is NOT a remake of Leaf Green. Fire Red is the counterpart to Leaf Green. Both are the same game except for a few version-exclusive Pokémon. It was the same case with the old Red and Blue games. I like the Pokémon in Fire Red better, but both complement Emerald nicely.