Customize messages in fboauth_action_connect()

Yeah, I'm not sure I'll add this. For most sites the default is okay and if not, yeah there's string overrides. You can also override strings directly in settings.php without string overrides (that module just provides an interface). We currently have 5 strings that users *might* want to override including:

t('You\'ve connected your account with Facebook.')
t('An account has been created for you on @sitename but an administrator needs to approve your account. In the meantime, a welcome message with further instructions has been sent to your e-mail address.', array('@sitename' => variable_get('site_name', '')))
t('Welcome to @sitename. Basic information has been imported from Facebook into your account. You may want to <a href="!edit">edit your account</a> to confirm the details and set a password.', array('@sitename' => variable_get('site_name', ''), '!edit' => url('user/' . $account->uid . '/edit')))
t('Your Facebook e-mail address does not match any existing accounts. If you have an account, you must first log in before you can connect your account to Facebook. Creation of new accounts on this site is disabled.')
t('Your account has been disconnected from Facebook.')

I'll probably pass on making these configurable through the UI.

One note, the most common message that would be changed is probably this one:

t('Welcome to @sitename. Basic information has been imported from Facebook into your account. You may want to <a href="!edit">edit your account</a> to confirm the details and set a password.', array('@sitename' => variable_get('site_name', ''), '!edit' => url('user/' . $account->uid . '/edit')))

Which I plan on not displaying if a custom URL is specified for registration as part of #1314940: Set Custom Landing Page URL for Login and Register. That will probably cover that use-case as much as necessary.