[gordner]

The oil slick was determined to not have originated from the aircraft, so at this time still no sign as I understand it.
The previous wing repair is a non issue, if you are getting on a commercial airliner there is a pretty slim chance it h as no damage history unless it is brand new, and in addition it appears that the aircraft merely had the winglet damaged and replaced, the aircraft can fly with very little effect with one winglet torn away. In fact, I know of a 777 that had winglet damage and had to relocate in order to be repaired and Boeing's recommended action was to cut off what was left of the winglet, speed tape the hole and fly the aircraft with one winglet to the repair location.
This event is remarkable in many ways, it is pretty hard to lose an aircraft these days. As far as location, the area in question is not an area that has systems that allow controllers to hard "paint"an aircraft, in areas such as this the "radar" system is really not a radar, it is the aircraft reporting her position to ATC, not ATC discerning her position by actual radar. So a significant transponder or nav system issue could have the aircraft reporting a gross postion error and everyone looking in the wrong area.