|I can answer 2 of those
Can you tell me what the hexagonal icon means at the end of some message (post) headers in the message lists? STOP sign - end of message - so you don't need to click on that actual message you are reading the entire message
Is there some way to find all replies made to me in one place, irregardless of the thread or forum? That would be your Mail box - up top - it shows the number of replies to your messages.
You may have Public replies and you may have private messages, only to you, that no one else sees