This is what I could manage –
1) For the first question, looks like this could be a bluehost specific thing. Pls read below for a solution –
http://voodoopress.com/send-your-wordpress-email-from-you-and-other-email-fixes/
http://wordpress.org/support/topic/subscribe2-sending-email-from-hosting-email-address
2) To change icon, pls follow instructions here – http://codex.wordpress.org/Creating_a_Favicon
Better – just use this plugin – http://wordpress.org/extend/plugins/all-in-one-favicon/
Hope this helps.