Re: Question about Esther:
Mordekhai had kept his relation to Esther a secret. So the place he met with her was at the kings gate. Now I suppose that Esther was not permitted out among the people, so she didnt know what had transpired (since it also says that the king had not sent for her in a month). I am sure she knew (being a jew) what sackcloth and ashes meant (lamenting and mourning), but didnt know the occasion for his distress. So I think it was meant to comfort him. And from Mordekhai actions we see he lets her know what is going on.
Now it seems to me there must have been some forknowledge on Mordekhai's part, since he changed her name and had her keep her identity a secret even from the king. Perhaps like Abraham who took Isaac to sacrifice him saying God himself would provide a lamb. Mordekhai tells Esther to break the law and go before the king.
So anyways as far as the happy clothes go, I think it was sent for consolement. She didnt know why he was distraught. And as his daughter (adopted) and queen, she was trying to help him. To show him that if she could she would make it alright. If it was me, and I saw my dad crying and mourning as for the loss of a loved one, I would try and comfort him. And definatly find out what was going on. Which is what I think was happening here.
"Anyone who does the will of my Father in heaven is my brother and sister and mother!"