I'm using a pc and for some reason no symbols or "emotions" are shown just boxes and dots. How can i fix that?
You cannot, although if you are using chrome there are emoji extensions that you can use to translate those boxes and even allow you to type some in. Alternatively there are other websites that you can search for which allow you to do the same.
I'm not sure as I tend not to do EE wars, but even if it did.. you'd just get back what you spent. The spells last til the end of the war, at minimum. So recasting is not necessary.
In that case, and don't quote me on this, but I believe there is a notification before war starts that tells you when you can cast spells for them to be added to potential earnings.
No. You can not cast the same spell multiple time for added winnings. You will not be refunded that in the case of your victory. It's a waste of mith.
Equipping items is a separate thing from profile stats, but are added to them during an action. You can look at equipment page to see the raw stat bonuses you are given. Castle gives smallll bonuses, so you just may have not noticed.