Thanks for playing and for your feedback! Some of these issues I am aware of.
Issue #1 I am aware of and it is an easy fix, just tedious. I will definitely fix that in a later update.
To solve issue #2, would you suggest that I add a penalty for any undeliverable item of mail? I hate to penalize the player on the first few days, but perhaps the postmaster could give them a 3-day grace period or somesuch so that after a few days it begins to penalize them.
Item 3.5 - don't worry, the postmaster comes in after you are finished to mail those properly! :)
3.75 - nope, you can still incorrectly mail letters if you do not use the auto-sorter! :)