Is there a way to download the entire series of chats by friend/username? There are some players that have given me great tips, but it takes forever to go page by page searching for the specific conversation applicable. If this is not possible, I would highly recommend a search/find feature, wherein you could input search paraments (i.e. username, date, key word(s), date range, etc.) Thank you!

Are you saying delete individual messages from a thread or remove the message thread from your list? If the latter, you can do this by clicking the gear icon at the top from within the chat thread and then clicking on yourself in the list to remove yourself.