Clarifications
The not so good:
Fernanset - that was an unmeasured response, perhaps you should too. Execs comment didn't suggest any aircraft, just this particular one and many of the senior LAMEs at MAS could tell the life story of their aircraft. The 777 has been a pretty well maintained fleet and I'd see no reason to doubt their judgement even in spite of the element of human error.
Physicus - it's RMAF Butterworth and has been for sometime, you're living in the 80's.
Slats11 - Meals, a bit too early still, people might have got a drink and peanuts if they were lucky. Skyshow, yes so they would have been able to watch position unless... IFE, yes would have been on after 10'000 so if not sleeping many would be watching. Phones, seriously from my experience there is no reception above 8000', momentary at best. Someone way back mentioned something about EPC (?) maybe that works but how many actually do it. As a digression one MAS 777 was a test aircraft for inflight GSM services (relayed through SATCOM). System was active in cruise, you could switch your phone on and make calls and sms only; the aircraft was it's own cell (charges were high of course). Success had a lot to do with your telco, mine didn't work, but for others it did.
The good:
V1...ooops - your ELT stuff is more or less correct. The tubular model is a Rescue406 and it floats like a buoy - in fact saltwater makes the battery cell work (if you use it on land you have to stick it in water or better yet urine), but there is nothing automatic with it other than in liquid it works and out it doesn't. The boxy unit quite often is an ADT406, it can be automatic (G switch) if armed but otherwise it's off and it can float if it's floatation collar is attached. But if they go to the bottom of the ocean they're not much use.
I was under the impression that all transport category aircraft had to carry an ELT and haven't flown a bird yet that doesn't have one "built-in" in addition to the portables stowed in the cabin (the built in one of course being armed at all times except in the hangar), at least on Boeing aircraft. For those wondering, the missing aircraft contains 1 fixed, 1 portable and 2 slide raft ELTs. The fixed one as per V1s description, the portable on it's own battery and the raft only when deployed in water (spose you could cut it out and drop it in water if you're the boy scout type). Only one unit is G-switched, the rest require human operation.
The Shadow - as someone said to me, plausible. However I would add that in my experience with unusual events affecting the airframe that post repair, said problem area is subjected to more routine inspections than normally required and that is Boeings recommendation. Eg hard-landing gear repairs every so many cycles, tail strike repairs every so many hours, etc. I rather doubt it would be fix it once and forget about it, monitoring would be required much like warped fan blades. I'm not an aerodynamicist, just a pilot, so won't tackle you on the theory, but as crew we get some stuffed up situations in the sim like runaway controls and while that can't mimic surface loss and the rolling moments could be significant, the outer 1/4 of the wing isn't contributing the majority of the lift so managable springs to mind in the best of situations. Regards to major repairs, much much earlier a MAS 777 tail striked in ZRH and it was "pretty" bad, whole tail redone, that aircraft is still flying.
Fly26 - the area you're referring to, it's pretty rugged for the most part and semi-mountainous depending where exactly. Nuri's and light aircraft have disappeared in there for ages and that makes sense due to their size but if a 777 went in with 30,000+kg of fuel onboard I think the haze problems here would be a whole lot worse.