To get multi-day sessions to display in the right order throughout the interface change the following line of the face_to_face_get_session_dates() function in facetoface/lib.php:
if ($dates = get_records('facetoface_sessions_dates', 'sessionid', $sessionid)) {
to:
if ($dates = get_records('facetoface_sessions_dates', 'sessionid', $sessionid, 'timestart')) {
That sorts the dates by start time when the sessions object is created. If you change a session date it should correct automatically.
A secondary issue is that only the first (with this fix, earliest) date of a multi-day session is displayed on the course page. I'm assuming this is by design and that having (multi-day) indicates that you should click through to see the other dates.
Logged as a bug here: http://tracker.moodle.org/browse/CONTRIB-1498