Hey!~
Regarding the mail delivery side-quest ~ It seems that you can't deliver the letter meant for T-Roy ~ can't interact with the mail box, n'or give it to the character by talking to him.
Is this intended per chance and you can't do that quest on the first day?
Also if the character is affected by a damage over time condition during battle, and the effect is not over by the time the fight ends, he will continue to take damage indefinitely after the fight ends.