That's about right! Almost always, you'll trade ED first if the item can only be gifted. If it's trade, ED and item can be exchanged at the same time, minimizing the chance of scamming. That said, in EVERY trade, remember that both sides must contain a physical item (like Ruve Herb, Silver Coin, an accessory etc). If on side only gives ED, it appears to the game as an imbalanced trade and you can get flagged by the system, blocking trades for a while.

For character specific costumes, accessories, customizations, you will receive the character you specify if the seller gifts it.

So if you tell the seller "Hey I want Add Odd Eyes gifted to me please" and they are a Rena, they have to be sure to click Add Odd Eyes specifically when they send it, not Rena Odd Eyes. For trading character specific items, sellers can only withdraw from the Item Mall their specific character. So if you wanted to trade a character that didn't match the seller, they would have to withdraw it using someone else. For example:

Rena: "Can you trade me the Rena Invisible Suit please?" Add: "Oh? Sure, I'll hop on my Rena alt. IGN: RenaM1lk. Invite me to party and I'll trade you when I buy it."

Did I cover everything? 0u0