BuddyPress.org

1. The main navigation is hard-coded into ‘header.php’. I don’t know of way to rearrange the order other than modifying that file itself.

2. There’s a great article about changing strings here:

https://codex.buddypress.org/how-to-guides/customizing-labels-messages-and-urls/

That being said, while your modifying the order in ‘header.php’ you can just change the strings there.

3. Not that I know of, although I haven’t thoroughly investigated.