The only one that is not right, for my meaning is the last one. Yearning really isn't the right word. It implies he's gonna be in the group, or something, doesn't it?

To yearn is to want something badly, with a sad overtone. It doesn't imply anything except how strongly you wish he would stay or miss him for leaving.

I know what it means. It just seems too strong a word, for one.

Online translators never work. It's impossible for a machine to translate from Japanese to English or vice-versa with any accuracy.

Trust Nagoyankee. He has no interest in screwing you over.

I didn't think he did.

You did read that part, right? It doesn't come off as strongly as the Cyclamen's translation in the original Japanese.

Nagoyankee is quite fluent in English, I'm sure he didn't write it to mean you're in love with the guy.

Well then, you could just say

「Methでのあなたがいなくてとても寂しいです。」
I miss you in Meth.

I know he didn't write it to mean that.

that's pretty much what I had wanted to say, I think. but it would have been I will, I think? anyway... mistakes or not. I had already sent it by the time I got most of these replies.

Don't take "yearn" too literally. That's as good as a translation as your going to get.

Wait, did you already send it, or are you going to use Nagoyankee's translation?

I unfortunately already sent it.