Quick Reply box is a default feature in SMF...
To enable it for yourself:
Profile -> Look and Layout
Set "Use quick reply on topic display" to "Show, on by default"
To enable it for guests and anyone who registers in the future:
Admin -> Themes and Layout -> Reset Options
Click "Reset the default (guest) options for this theme" under "SMF default theme"
Set "Use quick reply on topic display" to "Show, on by default"
To enable it for all current users:
Admin -> Themes and Layout -> Reset Options
Click "Reset all members' current options for this theme" under "SMF default theme"
Select "Change" next to "Use quick reply on topic display" and set it to "Show, on by default"
There are currently two different shoutbox mods that will work with 1.1.4:
nneonneo's ShoutboxSMF ShoutboxThe shoutbox mods modify BoardIndex.template.php, which isn't included in the Minerva theme (meaning the one from the default theme will be used), so the most you'll have to do to make them work properly on that theme is copy the images from the default theme.