Can I trade characters between my own two accounts? Like, put one char on sale and buy it with another of my own accounts for coins?

I have a decent multiboxing idea, but two chars that I need are on the same accounts and I'd have to level up one of those classes brand new, easier to trade it to my other account.

And is coin gifting between own accounts legal? I have some coins on my main accounts but I rly want to buy HC trinks for my prot pala on 2nd acc, can I just gift 46 coins? Ty