OK this is most definitely a bug / oversight on the part of Square Enix.

Within Final Fantasy 14 you can only mail people who are in your
friends list. You can not add an alternate character as a friend
when they are not online.

With out being able to make alternate charters "friends"
with each other there is no way to be able to send mail
back and forth between characters.

This is most definitely an oversight on the part of
SE.

This is very annoying and needs to be fixed!

We need to be able to have a way to be able to
send in game mail back and forth between alternate
characters.

A couple of suggestions on a fix for this would be
to allow friend requests between alternate characters
to be sent and then accepted when the alternate character
logs in.

Or Make it so that the moogle accepts mail from non-friends
and you can simply enter the name of the character and
mail people that way.

Can some one please look at this issue.

Thank you,